Fluid end

ABSTRACT

A flangeless fluid end comprising a fluid end body releasably attached to a connect plate. The connect plate is attached to a power source using stay rods. The flow bores of the fluid end are sealed without threading a retainer nut into the walls of each bore. Instead, the flow bores are sealed by bolting a retainer to the fluid end body. Plungers to drive fluid through the fluid end body are installed within removable stuffing box sleeves. These sleeves are maintained within the plunger bores by the bolted retainers. A number of features, including the location of seals within bore walls and carbide inserts within valve structures, aid in reducing or transferring wear.

RELATED APPLICATION

This application claims the benefit of provisional patent applicationSer. No. 62/777,705, authored by Nowell et al. and filed on Dec. 10,2018, the entire contents of which are incorporated herein by reference.

BACKGROUND

Various industrial applications may require the delivery of high volumesof highly pressurized fluids. For example, hydraulic fracturing(commonly referred to as “fracking”) is a well stimulation techniqueused in oil and gas production, in which highly pressurized fluid isinjected into a cased wellbore. As shown for example in FIG. 1, thepressured fluid flows through perforations 10 in a casing 12 and createsfractures 14 in deep rock formations 16. Pressurized fluid is deliveredto the casing 12 through a wellhead 18 supported on the ground surface20. Sand or other small particles (commonly referred to as “proppants”)are normally delivered with the fluid into the rock formations 16. Theproppants help hold the fractures 14 open after the fluid is withdrawn.The resulting fractures 14 facilitate the extraction of oil, gas, brine,or other fluid trapped within the rock formations 16.

Fluid ends are devices used in conjunction with a power source topressurize the fluid used during hydraulic fracturing operations. Asingle fracking operation may require the use of two or more fluid endsat one time. For example, six fluid ends 22 are shown operating at awellsite 24 in FIG. 2. Each of the fluid ends 22 is attached to a powerend 26 in a one-to-one relationship. The power end 26 serves as anengine or motor for the fluid end 22. Together, the fluid end 22 andpower end 26 function as a hydraulic pump.

Continuing with FIG. 2, a single fluid end 22 and its correspondingpower end 26 are typically positioned on a truck bed 28 at the wellsite24 so that they may be easily moved, as needed. The fluid and proppantmixture to be pressurized is normally held in large tanks 30 at thewellsite 24. An intake piping system 32 delivers the fluid and proppantmixture from the tanks 30 to each fluid end 22. A discharge pipingsystem 33 transfers the pressurized fluid from each fluid end 22 to thewellhead 18, where it is delivered into the casing 12 shown in FIG. 1.

Fluid ends operate under notoriously extreme conditions, enduring thesame pressures, vibrations, and abrasives that are needed to fracturethe deep rock formations shown in FIG. 1. Fluid ends may operate atpressures of 5,000-15,000 pounds per square inch (psi) or greater. Fluidused in hydraulic fracturing operations is typically pumped through thefluid end at a pressure of at least 8,000 psi, and more typicallybetween 10,000 and 15,000 psi. The power end used with the fluid endtypically has a power output of at least 2,250 horsepower duringhydraulic fracturing operations.

High operational pressures may cause a fluid end to expand or crack.Such a structural failure may lead to fluid leakage, which leaves thefluid end unable to produce and maintain adequate fluid pressures.Moreover, if proppants are included in the pressurized fluid, thoseproppants may cause erosion at weak points within the fluid end,resulting in additional failures.

It is not uncommon for conventional fluid ends to experience failureafter only several hundred operating hours. Yet, a single frackingoperation may require as many as fifty (50) hours of fluid endoperation. Thus, a traditional fluid end may require replacement afteruse on as few as two fracking jobs.

During operation of a hydraulic pump, the power end is not exposed tothe same corrosive and abrasive fluids that move through the fluid end.Thus, power ends typically have much longer lifespans than fluid ends. Atypical power end may service five or more different fluid ends duringits lifespan.

With reference to FIGS. 3 and 4, a traditional power end 34 is shown.The power end 34 comprises a housing 36 having a mounting plate 38formed on its front end 40. A plurality of stay rods 42 are attached toand project from the mounting plate 38. A plurality of pony rods 44 aredisposed at least partially within the power end 34 and project fromopenings formed in the mounting plate 38. Each of the pony rods 44 isattached to a crank shaft installed within the housing 36. Rotation ofthe crank shaft powers reciprocal motion of the pony rods 44 relative tothe mounting plate 38.

A fluid end 46 shown in FIGS. 3 and 4 is attached to the power end 34.The fluid end 46 comprises a fluid end body 48 having a flange 50machined therein. The flange 50 provides a connection point for theplurality of stay rods 42. The stay rods 42 rigidly interconnect thepower end 34 and the fluid end 46. When connected, the fluid end 46 issuspended in offset relationship to the power end 34.

A plurality of plungers 52 are disposed within the fluid end 46 andproject from openings formed in the flange 50. The plungers 52 and ponyrods 44 are arranged in a one-to-one relationship, with each plunger 52aligned with and connected to a corresponding one of the pony rods 44.Reciprocation of each pony rod 44 causes its connected plunger 52 toreciprocate within the fluid end 46. In operation, reciprocation of theplungers 52 pressurizes fluid within the fluid end 46. The reciprocationcycle of each plunger 52 is differently phased from that of eachadjacent plunger 52.

With reference to FIG. 6, the interior of the fluid end 46 includes aplurality of longitudinally spaced bore pairs. Each bore pair includes avertical bore 56 and an intersecting horizontal bore 58. The zone ofintersection between the paired bores defines an internal chamber 60.Each plunger 52 extends through a horizontal bore 58 and into itsassociated internal chamber 60. The plungers 52 and horizontal bores 58are arranged in a one-to-one relationship.

Each horizontal bore 58 is sized to receive a plurality of packing seals64. The seals 64 are configured to surround the installed plunger 54 andprevent high pressure fluid from passing around the plunger 52 duringoperation. The packing seals 64 are maintained within the bore 58 by aretainer 65. The retainer 65 has external threads 63 that mate withinternal threads 67 formed in the walls surrounding the bore 58. In sometraditional fluid ends, the packing seals 64 are installed within aremovable stuffing box sleeve that is installed within the horizontalbore.

Each vertical bore 56 interconnects opposing top and bottom surfaces 66and 68 of the fluid end 46. Each horizontal bore 58 interconnectsopposing front and rear surfaces 70 and 72 of the fluid end 46. Adischarge plug 74 seals each opening of each vertical bore 56 on the topsurface 66 of the fluid end 46. Likewise, a suction plug 76 seals eachopening of each horizontal bore 58 on the front surface 70 of the fluidend 46.

Each of the plugs 74 and 76 features a generally cylindrical body. Anannular seal 77 is installed within a recess formed in an outer surfaceof that body, and blocks passage of high pressure fluid. The body ofeach of the plugs 74 and 76 has a uniform diameter along most or all ofits length. When the plugs 74 and 76 are installed within thecorresponding bores 56 and 58, little to no clearance exists between theouter surface of the body and the walls surrounding the bores.

The discharge and suction plugs 74 and 76 are retained within theircorresponding bores 56 and 58 by a retainer 78, shown in FIGS. 3, 5, and6. The retainer 78 has a cylindrical body having external threads 79formed in its outer surface. The external threads 79 mate with internalthreads 81 formed in the walls surrounding the bore 56 or 58 above theinstalled plug 74 or 76.

As shown in FIGS. 3 and 4, a manifold 80 is attached to the fluid end46. The manifold 80 is also connected to an intake piping system, of thetype shown in FIG. 2. Fluid to be pressurized is drawn from the intakepiping system into the manifold 80, which directs the fluid into each ofthe vertical bores 56, by way of openings (not shown) in the bottomsurface 68.

When a plunger 52 is retracted, fluid is drawn into each internalchamber 60 from the manifold 80. When a plunger 52 is extended, fluidwithin each internal chamber 60 is pressurized and forced towards adischarge conduit 82. Pressurized fluid exits the fluid end 46 throughone or more discharge openings 84, shown in FIGS. 3-5. The dischargeopenings 84 are in fluid communication with the discharge conduit 82.The discharge openings 84 are attached to a discharge piping system, ofthe type shown in FIG. 2.

A pair of valves 86 and 88 are installed within each vertical bore 56,on opposite sides of the internal chamber 60. The valve 86 preventsbackflow in the direction of the manifold 80, while the valve 88prevents backflow in the direction of the internal chamber 60. Thevalves 86 and 88 each comprise a valve body 87 that seals against avalve seat 89.

Traditional fluid ends are normally machined from high strength alloysteel. Such material can corrode quickly, leading to fatigue cracks.Fatigue cracks occur because corrosion of the metal decreases themetal's fatigue strength—the amount of loading cycles that can beapplied to a metal before it fails. Such cracking can allow leakage thatprevents a fluid end from achieving and maintaining adequate pressures.Once such leakage occurs, fluid end repair or replacement becomesnecessary.

Fatigue cracks in fluid ends are commonly found in areas that experiencehigh stress. For example, with reference to the fluid end 46 shown inFIG. 6, fatigue cracks are common at a corner 90 formed in the interiorof the fluid end 46 by the intersection of the walls surrounding thehorizontal bore 58 with the walls surrounding the vertical bore 56. Aplurality of the corners 90 surround each internal chamber 60. Becausefluid is pressurized within each internal chamber 60, the corners 90typically experience the highest amount of stress during operation,leading to fatigue cracks.

Fatigue cracks are also common at the neck that connects the flange 50and the fluid end body 48. Specifically, fatigue cracks tend to form atan area 92 where the neck joins the body 48, as shown for example inFIGS. 4-6. Flanged fluid ends require sufficient space between theflange and the fluid end body so that a wrench can be manipulated withinthe gap. During operation, the pumping of high pressure fluid throughthe fluid end causes it to pulsate or flex. Such motion results in atorque at the fluid end. The magnitude of torque applied at the fluidend is proportional to the distance between the power end and the frontsurface of the fluid end body: the moment arm. Such distance is extendedwhen a flange is interposed between the power end and the fluid endbody.

In the fluid end 46, for example, the space between the flange 50 andthe fluid end body 48 lengthens the moment arm that terminates at thebody 48. As a result of this lengthening, pulsation of the fluid end 46produces a torque of greater magnitude at the body 48. This increase intorque magnitude produces greater stress at the area 92, with fatiguecracks eventually resulting.

Additional failure points are commonly found around the discharge andsuction plugs 74 and 76 and the packing seals 64, shown in FIG. 6. Overtime, the seals 53 and packing seals 64 cause erosion of the wallssurrounding the bores 56 and 58. As a result, fluid begins to leakaround the plugs 74 and 76 and around the packing seals 64.

Further, because the plugs 74 and 76 fit tightly within theircorresponding bores 56 and 58, the plugs are also difficult to installwithin and remove from the fluid end 46. Significant forces may beneeded during installation and removal of these plugs, resulting inscratching or scraping of the walls surrounding the bores 56 and 58.Fluid may eventually leak around the plugs 74 and 76 in the scratched orscraped areas, causing the fluid end to fail.

Failure points are also commonly found around the retainers 65 and 78.These retainers are installed within the bores 56 and 58 via threads.Over time, the cyclical pulsations of the fluid end 46 may cause theretainers 65 and 78 to back-out slightly, allowing the retainer 65 or 78to move relative to the fluid end 46. Such motion may result in crackedthreads or fractures in the walls surrounding the bores 56 or 58.

The large torques required to install and remove the retainers 65 or 78can also produce cracking of the threads. Such cracking may result influid leakage, or may altogether prevent removal of the retainer fromthe fluid end 46. In such case, the fluid end 46 will need to berepaired or discarded.

During operation, it is also common for the valves 86 and 88 to wear andno longer properly seal. A sealing surface on the valve seat 89typically experiences the most wear, requiring the valve seats 89 to bereplaced during operation. It is not uncommon for a valve seat 89 torequire replacement after every forty (40) hours of fluid end operation.

With reference to FIG. 6A, fatigue cracks may also occur in the wallssurrounding the vertical bore 56 adjacent the valves 86 and 88. Thevalve seats 89 each have an upper flange 96 joined to a cylindricallower body 98. When the valve seat 89 is installed within the verticalbore 56, the flange 96 engages a corner 99 formed in the wallssurrounding the bore 56. The corner 99 traditionally has an angle α ofless than 180 degrees. During operation of a fluid end, the corner 99experiences high levels of stress. Over time, this stress may cause thewalls at the corner 99 to crack, leading to failure of the fluid end 46.

For the above reasons, there is a need in the industry for a fluid endconfigured to avoid or significantly delay the structures or conditionsthat cause wear or failures within a fluid end.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of the underground environment of a hydraulicfracturing operation.

FIG. 2 illustrates above-ground equipment used in a hydraulic fracturingoperation.

FIG. 3 is a left side perspective view of a traditional fluid endattached to a traditional power end.

FIG. 4 is a left side elevational view of the fluid end and power endshown in FIG. 3.

FIG. 5 is a top plan view of the fluid end shown in FIGS. 3 and 4.

FIG. 6 is a sectional view of the fluid end shown in FIG. 5, taken alongline A-A.

FIG. 6A is an enlarged and cross-sectional view of area AA, shown inFIG. 6.

FIG. 7 is a left side perspective view of one embodiment of a fluid end,attached to a power end identical to that shown in FIGS. 3 and 4.

FIG. 8 is a left side elevational view of the fluid end and power endshown in FIG. 7.

FIG. 9 is a front perspective view of the fluid end shown in FIGS. 7 and8.

FIG. 10 is a rear perspective view of the fluid end shown in FIG. 9.

FIG. 11 is a top plan view of the fluid end shown in FIG. 9.

FIG. 12 is a front perspective view of the power end shown in FIGS. 7and 8. No attached fluid end is shown.

FIG. 13 is a front perspective view of the connect plate of the fluidend shown in FIG. 9.

FIG. 14 is a front perspective view showing the power end of FIG. 12,with the connect plate of FIG. 13 installed. A washer and nut used toengage one of the stay rods are shown in exploded form.

FIG. 15 is a left side elevation view of the power end and connect plateshown in FIG. 14. The connect plate and stay rods are shown incross-section. The cross-section is taken along a plane that includesline CC-CC from FIG. 14.

FIG. 16 is an exploded front perspective view of the fluid end shown inFIG. 9. Only a single plunger is shown.

FIG. 17 is an exploded rear perspective view of the fluid end shown inFIG. 10.

FIG. 18 is a cross-sectional view of the fluid end shown in FIG. 11,taken along line C-C.

FIG. 19 is an enlarged view of area D from FIG. 18.

FIG. 20 is an enlarged view of area E from FIG. 18.

FIG. 21 is an enlarged view of area F from FIG. 18.

FIG. 22 is an enlarged view of area G from FIG. 18.

FIG. 23 is an enlarged view of area H from FIG. 18.

FIG. 24 is a cross-sectional view of the fluid end shown in FIG. 11,taken along line I-I.

FIG. 25 is an enlarged view of area J from FIG. 24.

FIG. 26 is an enlarged view of area K from FIG. 24.

FIG. 27 is an enlarged view of area L from FIG. 24.

FIG. 28 is a top perspective view of a suction plug used with the fluidend shown in FIGS. 18 and 24.

FIG. 29 is a side elevation view of the suction plug shown in FIG. 28.

FIG. 30 is a cross-sectional view of the suction plug shown in FIG. 29,taken along line M-M.

FIG. 31 is an enlarged view of area N shown in FIG. 19.

FIG. 32 is a top perspective view of a discharge plug used with thefluid end shown in FIGS. 18 and 24.

FIG. 33 is a side elevational view of the discharge plug shown in FIG.32.

FIG. 34 is a cross-sectional view of the discharge plug shown in FIG.33, taken along line O-O.

FIG. 35 is an enlarged view of area P shown in FIG. 20.

FIG. 36 is a top perspective view of a retainer used with the fluid endshown in FIGS. 18 and 24.

FIG. 37 is a top perspective view of a retainer nut that may beinstalled within the retainer shown in FIG. 36.

FIG. 38 is a bottom perspective view of the retainer nut shown in FIG.37.

FIG. 39 is a side elevation view of a stud used with the retainer shownin FIG. 36.

FIG. 40 is a top perspective view of a stuffing box sleeve used with thefluid end in FIGS. 18 and 24.

FIG. 41 is a bottom perspective view of the stuffing box sleeve shown in

FIG. 40.

FIG. 42 is a side elevational view of the stuffing box sleeve shown inFIGS. 40 and 41.

FIG. 43 is a cross-sectional view of the stuffing box sleeve, takenalong lines Q-Q in FIG. 42.

FIG. 44 is a top perspective view of another embodiment of a retainerused with the fluid end shown in FIGS. 18 and 24.

FIG. 45 is a bottom perspective view of the retainer shown in FIG. 44.

FIG. 46 is a top perspective view of a packing nut used with the fluidend shown in FIGS. 18 and 24.

FIG. 47 is a bottom perspective view of the packing nut shown in FIG.46.

FIG. 48 is a top perspective view of a valve seat used with the fluidend shown in FIGS. 18 and 24.

FIG. 49 is a bottom perspective view of the valve seat shown in FIG. 48.

FIG. 50 is a side elevation view of the valve seat in FIGS. 48 and 49.

FIG. 51 is a cross-sectional view of the valve seat shown in FIG. 50,taken along line R-R.

FIG. 52 is a top perspective view of a valve body used with the fluidend shown in FIGS. 18 and 24.

FIG. 53 is a bottom perspective view of the valve body shown in FIG. 52.

FIG. 54 is a side elevation view of the valve body in FIGS. 52 and 53.

FIG. 55 is a rear perspective view of another embodiment of a fluid end.

FIG. 56 is a top plan view of the fluid end shown in FIG. 55

FIG. 57 is an exploded front perspective view of the fluid end shown inFIG. 55. Only a single plunger is shown.

FIG. 58 is a rear perspective view of the fluid end shown in FIG. 57.

FIG. 59 is a cross-sectional view of the fluid end shown in FIG. 56,taken along line S-S.

FIG. 60 is a cross-sectional view of the fluid end shown in FIG. 56,taken along line T-T.

FIG. 61 is a top perspective view of a stuffing box sleeve used with thefluid end shown in FIGS. 59 and 60.

FIG. 62 is a bottom perspective view of the stuffing box sleeve shown inFIG. 61.

FIG. 63 is a top perspective view of a retainer used with the fluid endshown in FIGS. 59 and 60.

FIG. 64 is a bottom perspective view of the retainer shown in FIG. 63.

FIG. 65 is a front perspective view of another embodiment of a fluidend.

FIG. 66 is a rear perspective view of the fluid end shown in FIG. 65.

FIG. 67 is a top plan view of the fluid end shown in FIG. 65.

FIG. 68 is an exploded front perspective view of the fluid end shown inFIG. 65. Only a single plunger is shown.

FIG. 69 is a rear perspective view of the fluid end shown in FIG. 68.

FIG. 70 is a cross-sectional view of the fluid end shown in FIG. 67,taken along line U-U.

FIG. 71 is a cross-sectional view of the fluid end shown in FIG. 67,taken along line V-V.

FIG. 72 is a top perspective view of a discharge plug shown installed inthe fluid end in FIG. 70.

FIG. 73 is a bottom perspective view of the discharge plug shown in FIG.72.

FIG. 74 is a side elevation view of the discharge plug shown in FIGS. 72and 73.

FIG. 75 is a cross-sectional view of the discharge plug shown in FIG.74, taken along line W-W.

FIG. 76 is a top perspective view of a retainer used with the dischargeplug shown in FIG. 72.

FIG. 77 is a bottom perspective view of the retainer shown in FIG. 76.

FIG. 78 is the front perspective view of the fluid end shown in FIG. 9,with an installed safety system.

FIG. 79 is a cross-sectional view of the fluid end and safety systemshown in FIG. 78, taken along a plane that includes line X-X.

The Following Figures Illustrate Additional Embodiments Discussed withRespect to Appendices A-J

FIG. 80 is a partially exploded view of a first embodiment of a fluidend. FIG. 80 shows a suction and discharge end of the fluid end.

FIG. 81 is a partially exploded view of a plunger end of the fluid endbody shown in FIG. 80.

FIG. 82 is a cross-sectional view of the fluid end shown in FIG. 80,taken along line A-A.

FIG. 83 is a partially exploded view of a second embodiment of a fluidend. FIG. 83 shows a suction and discharge end of the fluid end.

FIG. 84 is a partially exploded view of a plunger end of the fluid endbody shown in FIG. 83.

FIG. 85 is a cross-sectional view of the fluid end shown in FIG. 83,taken along line B-B.

FIG. 86 is a partially exploded view of a third embodiment of a fluidend. FIG. 86 shows a suction and discharge end of the fluid end.

FIG. 87 is a partially exploded view of a plunger end of the fluid endbody shown in FIG. 86.

FIG. 88 is a partially exploded view of a fifth embodiment of a fluidend. FIG. 88 shows a suction and discharge end of the fluid end.

FIG. 89 is a partially exploded view of a plunger end of the fluid endbody shown in FIG. 88.

FIG. go is a cross-sectional view of the fluid end shown in FIG. 88,taken along line C-C.

FIG. 91 is a partially exploded view of a sixth embodiment of a fluidend. FIG. 91 shows a suction and discharge end of the fluid end.

FIG. 92 is a cross-sectional view of the fluid end shown in FIG. 91,taken along line D-D.

FIG. 93 is a partially exploded view of a seventh embodiment of a fluidend. FIG. 93 shows a suction and discharge end of the fluid end.

FIG. 94 is a side elevational view of one of the plurality of studs foruse with the fluid ends.

FIG. 95 is a right side elevational view of the fluid end shown in FIG.9. Portions of the fluid end are shown in dashed lines.

FIG. 96 is a front elevational view of the fluid end shown in FIG. 95.

FIG. 97 is a left side elevational view of the fluid end shown in FIG.95.

FIG. 98 is a rear elevational view of the fluid end shown in FIG. 95.

FIG. 99 is a bottom plan view of the fluid end shown in FIG. 95.

FIG. 100 is a top plan view of the fluid end shown in FIG. 95.

FIG. 101 is a front perspective view of the fluid end shown in FIG. 95.

FIG. 102 is a rear perspective view of the fluid end shown in FIG. 95.

FIG. 103 is a sectional side view of a fluid end having a prior artvalve seat for explanatory purposes

FIG. 104 is a sectional side view of a fluid end having a tapered valveseat.

FIG. 105A is a side view of the valve seat shown in FIG. 81.

FIG. 105B is a sectional view of the valve seat of FIG. 105A along lineA-A.

FIG. 106A is a side view of an alternative valve seat.

FIG. 106B is a sectional view of the valve seat of FIG. 106A along lineA-A.

FIG. 107 is a sectional side view of a fluid end having a tapered valveseat containing an insert.

FIG. 108A is a sectional side view of a valve seat containing an insert.

FIG. 108B is a sectional side view of a valve seat containing an insert.

FIG. 108C is a sectional side view of a valve seat containing an insert.

FIG. 109A is a sectional side view of a fluid end having a tapered valveseat.

FIG. 109B is a detail view of a gap between the tapered valve seat andvalve bore shown in FIG. 109A.

FIG. 110 is a cutaway perspective view of the valve seat shown in FIGS.109A and 109B.

FIG. in is a cross-sectional side view of a fluid end.

FIG. 112 is a sectional perspective view of a valve having a stem.

FIG. 113 is a sectional perspective view of a valve having a stem incommunication with a valve retainer.

FIG. 114 is a sectional side view of an alternative valve seat and fluidend.

FIG. 115 is a sectional perspective view of a valve.

FIG. 116 is a sectional perspective view of a valve in communicationwith a valve retainer.

FIG. 117 is a sectional side view of an alternative valve seat and fluidend.

FIG. 118 is a top perspective view of a valve body.

FIG. 119 is a sectional view of the valve of FIG. 118 within a fluid endbore.

FIG. 120 is a sectional view of the valve of FIG. 118 within a fluid endbore in communication with a valve retainer.

FIG. 121 is a sectional view of a fluid end with a top valve in a closedposition and a bottom valve in an open position.

FIG. 122 is a top perspective view of a valve body.

FIG. 123 is a sectional view of the valve of FIG. 122 within a fluidend.

FIG. 124 is a sectional view of the valve of FIG. 122 within a fluid endbore in communication with a valve retainer.

FIG. 125 is an exploded perspective view of a fluid end.

FIG. 126 is a sectional side view of the fluid end of FIG. 125 alongsection A-A.

FIG. 127 is a bottom side perspective of a prior art valve body.

FIG. 128 is a bottom side perspective view of the fluid end valve body.

FIG. 129 is a side view of the fluid end valve body of FIG. 128.

FIG. 130 is a cutaway sectional side view of a fluid end bore with thevalve body of FIG. 128 disposed therein.

FIG. 131 is a side view of a valve and valve seat.

FIG. 132 is a side view of a valve and valve seat.

FIG. 133 is a sectional view of a fluid end with an adjustable valve.

FIG. 134 is an isometric depiction of a fluid end that is constructed inaccordance with embodiments of this technology.

FIG. 135 is an enlarged depiction of a portion of the fluid end of FIG.88.

FIG. 136 is an exploded cross-sectional depiction of a fluid end that isconstructed in accordance with embodiments of this technology.

FIG. 137 is an enlarged depiction of portions of the fluid end of FIG.136.

FIG. 138 is an enlarged depiction of portions of the fluid end of FIG.136.

FIG. 139 is a cross-sectional depiction of another fluid end that isconstructed in accordance with embodiments of this technology.

FIG. 140 is an enlarged depiction of portions of the fluid end of FIG.139.

FIG. 141 is an enlarged depiction of portions of the fluid end of FIG.139.

FIG. 142 is a top front right perspective view of a fluid end.

FIG. 143 is a top front right sectional view of the fluid end of FIG.142.

FIG. 144 an exploded view of the fluid end shown in FIG. 142.

FIG. 145 is a top front right sectional view of one section of the fluidend of FIG. 142.

FIG. 146 is a side sectional view of a fluid end with the bellows in aretracted position.

FIG. 147 is a side sectional view of the fluid end of FIG. 146 with thebellows in an extended position.

FIG. 148 is a rear sectional view of the fluid end of FIG. 147 takenalong section A-A.

FIG. 149 is a perspective view of a suction plug.

FIG. 150 is a perspective view of a discharge plug.

FIG. 151 is a cross-sectional view of a fluid end.

FIG. 152 is a detail B view of FIG. 152.

FIG. 153 is a perspective view of a fluid end attached to a power end.

FIG. 154 is a side elevation view of the fluid end and power end shownin FIG. 80.

FIG. 155 is a cross-sectional view of the fluid end shown in FIG. 153,taken along line A-A. The inlet manifold has been removed for clarity.

FIG. 156 is a cross-sectional view of the fluid end shown in FIG. 155.The inner and outer components of the fluid end have been removed forclarity.

FIG. 157 is a cross-sectional view of the fluid end shown in FIG. 153,taken along line B-B. The inlet manifold has been removed for clarity.

FIG. 158 is a partially exploded perspective view of a back side of thefluid end. A plurality of stay rods used to attach the fluid end to thepower end are shown installed within a second body of the fluid end.

FIG. 159 is a perspective view of the power end shown in FIG. 153 withthe stay rods attached thereto. The fluid end has been removed forclarity.

FIG. 160 is a perspective view of a front side of the second body of thefluid end shown in FIG. 158. The components installed within the secondbody have been removed for clarity.

FIG. 161 is a perspective view of the power end of FIG. 159 with thesecond body of FIG. 160 attached thereto. The first body of the fluidend has been removed for clarity. A portion of the fastening system usedto secure the second body to the power end is shown exploded forreference.

FIG. 162 is a side elevation view of the power end and attached secondbody shown in FIG. 161. The second body and stay rods attaching thesecond body to the power end are shown in cross-section.

FIG. 163 is a perspective view of a back side of an alternativeembodiment of a fluid end.

FIG. 164 is a cross-sectional view of the fluid end shown in FIG. 163,taken along line C-C.

FIG. 165 is a cross-sectional view of the fluid end shown in FIG. 163,taken along line D-D.

FIG. 166 is a perspective view of a fluid end known in the art attachedto a power end.

FIG. 167 is a side elevation view of the fluid end and power end shownin FIG. 166.

DETAILED DESCRIPTION

To avoid or significantly delay the failures typically seen intraditional fluid ends and described above, the inventors re-engineeredmany features of a traditional fluid end. One embodiment of suchengineering, a fluid end 100, is shown in FIGS. 7-11. The variousfeatures of the fluid end 100 and alternative embodiments of thosefeatures are described below.

With reference to FIGS. 7-11, one of the features of a traditional fluidend that the inventors re-engineered was the flange. As discussed above,fatigue failures in fluid ends are commonly found around the flange.Thus, the fluid end too has no flange. Without a flange, the moment armassociated with the fluid end 100 is significantly decreased. Therefore,less torque is applied to the fluid end too during operation thanflanged fluid ends, making the fluid end too less susceptible to fatiguefailures.

One approach to overcoming the drawbacks of a machined flange would beto remove the flange and attach the power end's stay rods directly tothe fluid end body. However, in order to secure the stay rods to thefluid end body, the stay rods must extend entirely through the fluid endbody. This construction requires the use of specially designed powerends having longer-than-usual stay rods. An operator may not always havea fleet of such power ends at its disposal.

The fluid end too was designed so that is can be attached to atraditional power end 34, as shown in FIGS. 7 and 8. Such attachment ispossible because the fluid end 100 has a multi-piece body design.Instead of extending stay rods entirely through a single fluid end body,the stay rods 42 are attached to one of the pieces of the multi-piecebody.

While not a cause of a failure, machining a flange into the fluid endalso entails the wastage of a significant amount of removed rawmaterial. Such machining also requires a significant investment of timeand labor, thus resulting in increased manufacturing costs. For fluidends that use a single fluid end body design, extra machining may beneeded to help decrease the thickness of the fluid end body. Forexample, some of the bores may be machined to project from the surfaceof the fluid end body. Material around the projecting bores may bediscarded and wasted. In contrast, the combination of the flangeless andmulti-piece body design of the fluid end 100 uses fewer raw materials,reducing material wastage and manufacturing costs.

Continuing with FIGS. 7-11, the fluid end 100 comprises a fluid end body102 releasably attached to a connect plate 104. The fluid end body 102and the connect plate 104 are each generally shaped as a rectangularprism and have the same length and height. During operation, fluid ismostly contained within the fluid end body 102. The connect plate 104serves primarily as a connection point for the stay rods 42. Thus, theconnect plate 104, may be thinner than the fluid end body 102 (thicknessbeing measured in FIG. 11 along the line B-B, for example).

When the fluid end body 102 is attached to the connect plate 104, thefluid end 100 has the shape of a rectangular prism. However, one or moreof the corners of the prism may be beveled. In alternative embodiments,the width and height of the connect plate may vary from the length andheight of the fluid end body. In further alternative embodiments, theconnect plate and the fluid end body may have the same thickness.

Continuing with FIGS. 9-11, the fluid end body 102 is joined to theconnect plate 104 such that a rear surface 106 of the fluid end body 102faces a front surface 108 of the connect plate 104. In some embodiments,the fluid end body 102 and the connect plate 104 are attached such thata portion of the rear surface 106 of the fluid end body 102 is in flushengagement with a portion of the front surface 108 of the connect plate104.

With reference to FIGS. 12, 14, and 15, the stay rods 42 rigidlyinterconnect the connect plate 104 and the power end 34. A traditionalstay rod, like the stay rods 42, comprises an elongate body 110 havingopposed first and second ends 112 and 114. External threads are formedin the body 110 adjacent each of its ends 112 and 114. These threadedportions of the body 110 are of lesser diameter than the rest of thebody 110. A step separates each threaded portion of the body no from itsunthreaded portion. Step 116 is situated adjacent its first end 112 andstep 118 is situated adjacent its second end 114, as shown in FIGS. 12and 15.

A plurality of internally threaded openings are formed about theperiphery of the mounting plate 38. Each threaded opening mates with athreaded first end 112 of one of the stay rods 42 in a one-to-onerelationship. An integral nut 120 is formed in each stay rod 42 adjacentits first end 112. The nut 120 provides a gripping surface where torquemay be applied to the stay rod 42 when installing the stay rod 42 in themounting plate 38. Once a stay rod 42 has been installed in the mountingplate 38, the elongate body no and second end 114 project from the frontsurface of the mounting plate 38, as shown in FIG. 12. In alternativeembodiments, the stay rods may be installed within threaded connectorssupported on the mounting plate.

With reference to FIGS. 13-15, a plurality of bores 126 are formed aboutthe periphery of the connect plate 104 for receiving the second end 114of each stay rod 42, as shown in FIG. 15. Each of the bores 126 opens onthe front surface 108 and rear surface 124 of the connect plate 104. Thenumber of bores 126 is equal to the number of stay rods 42, and thebores 126 are positioned such that they are alignable with the stay rods42 in a one-to-one relationship. In alternative embodiments, the boresin the connect plate may be spaced so as to match different stay rodspacing configurations used with different power ends.

A counterbore 128 is formed in each bore 126 adjacent the front surface108 of the connect plate 104. Adjacent counterbores 128 may overlap eachother, as shown in FIG. 13. In alternative embodiments, each bore may bespaced from each adjacent bore such that their respective counterboresdo not overlap.

Continuing with FIG. 15, a stay rod 42 is installed within one of thebores 126 by inserting its second end 114 into the opening of the bore126 formed on the rear surface 124 of the connect plate 104. The stayrod 42 is extended into the bore 126 until the step 118 abuts the rearsurface 124. When a stay rod 42 is installed, its second end 114projects within the counterbore 128 of its associated bore 126. Tosecure each stay rod 42 to the connect plate 104, a washer 130 and nut132 are installed on the second end 114 of the stay rod 42, as shown inFIGS. 14 and 15. Once installed, each nut 132 and its underlying washer130 press against a flat bottom 134 of a counterbore 128 within whichthey are installed. The nut 132 is fully contained within thatcounterbore 128.

Turning to FIGS. 16 and 17, the fluid end body 102 is secured to theconnect plate 104 using a fastening system 136. The fastening system 136comprises a plurality of studs 138, a plurality of washers 140, andplurality of internally threaded nuts 142. Each stud 138 comprises acylindrical body 144 having a pair of opposed ends 146 and 148. Each ofthe ends 146 and 148 is externally threaded.

Continuing with FIG. 17, a plurality of internally threaded openings 150are formed about the periphery of the rear surface 106 of the fluid endbody 102. The first end 146 of each stud 138 mates with a correspondingone of the openings 150. Once a stud 138 has been installed in the fluidend body 102, its second end 148 projects from the body's rear surface106.

With reference to FIGS. 13, 16 and 17, a plurality of through-bores 152are formed about the periphery of the connect plate 104. Thethrough-bores 152 are alignable with the plural studs 138 projectingfrom the fluid end body 102.

To assemble the fluid end 100, the plural studs 138 are installed in theplural openings 150 of the fluid end body 102. The fluid end body 102and installed studs 138 are positioned such that each through-bore 152formed in the connect plate 104 is aligned with a corresponding stud138. The fluid end body 102 and the connect plate 104 are then broughttogether such that each stud 138 is received within a correspondingthrough-bore 152.

When the fluid end body 102 and the connect plate 104 are thus joined,the second end 148 of each stud 138 projects from the rear surface 124of the connect plate 104, as shown in FIGS. 18 and 24. Finally, thewasher 140 and nut 142 are installed on the second end 148 of each stud138, as shown in FIGS. 10, 11, 18, and 24. The nut 142 is turned untilit presses against the rear surface 124 of the connect plate 104,thereby securing the fluid end body 102 and the connect plate 104together.

Continuing with FIG. 17, one or more pin bores 154 may be formed in therear surface 106 of the fluid end body 102 adjacent its outer edges.Each pin bore 154 may receive a pin 160 that projects from the rearsurface 106 of the fluid end body 102. These pins 160 may be installedwithin a corresponding bore 162 formed in the connect plate 104, asshown in FIG. 16. The pins 160 help align the fluid end body 102 and theconnect plate 104 during assembly of the fluid end 100.

The fluid end body 102 and the connect plate 104 may each be formed froma strong, durable material, such as steel. As discussed above,traditional fluid ends are formed from a high strength alloy steel thattends to erode quickly under of the constant flow of high pressurefluid. In order to extend the life of the fluid end 100, the inventorsformed the fluid end body 102 out of stainless steel. Stainless steelerodes at a much slower rate than traditional high strength alloy steel.Stainless steel also has a much longer fatigue life than high strengthalloy steel. Thus, by making the fluid end body 102 out of stainlesssteel, the fluid end 100 is much less susceptible to fatigue cracks.Therefore, the life of the fluid end 100 is significantly increased fromthat of a traditional fluid end.

In contrast, because the connect plate 104 serves primarily as aconnection point for the stay rods 42, it can be formed from adifferent, lower strength, and less costly material than the fluid endbody 102. For example, when the fluid end body 102 is formed fromstainless steel, the connect plate 104 can be formed from a less costlyalloy steel, such as 1020 alloy steel. Alternatively, the fluid end body102 and the connect plate 104 may be formed from the same material, suchas stainless steel.

In order to manufacture the fluid end 100, the fluid end body 102 andthe connect plate 104 are each cut to size from blocks of the chosensteel. The block used to create the fluid end body 102 is preferably aforged block of steel. Multiple fluid end bodies may be formed from thesame block. In such case, a block may be divided lengthwise intomultiple rectangular pieces, with each piece to form a fluid end body.Because no flanges will be machined from the block, the materialformerly dedicated to flanges can be reassigned to other pieces, fromwhich additional fluid end bodies can be formed. Multiple connect platesmay likewise be formed from the same block. If the fluid end body andthe connect plate are formed from the same material, the fluid end bodyand connect plate may be formed from the same block.

In alternative embodiments, the flangeless, multi-piece fluid end may beformed in accordance with those embodiments shown in Appendix J.

With reference now to FIGS. 18 and 24, the interior of the fluid endbody 100 includes a plurality of longitudinally spaced bore pairs. Eachbore pair includes a vertical bore 164 and an intersecting horizontalbore 166. The zone of intersection between the paired bores defines aninternal chamber 168.

As previously discussed with regard to FIG. 6, a plurality of corners goare formed in the walls surrounding the internal chamber 60 of atraditional fluid end. Such corners 90 experience a high amount ofstress and are thus prone to fatigue cracks. The inventors of the fluidend 100 determined that stress concentrations at the corners 90 aresignificantly reduced if the corners are beveled. Thus, in the fluid endbody 102, a plurality of corners 170 surrounding each internal chamber168 are beveled. More preferably, all of the corners 170 surroundingeach internal chamber 168 are beveled.

Continuing with FIGS. 18 and 24, each vertical bore 164 interconnectsopposing top and bottom surfaces 172 and 174 of the fluid end body 102.Each horizontal bore 166 interconnects opposing front and rear surfaces176 and 106 of the fluid end body 102. A plurality of longitudinallyspaced horizontal bores 178 are also formed in the connect plate 104, asshown in FIG. 13. The bores 178 interconnect the front and rear surfaces108 and 124 of the connect plate 104. When the fluid end 100 isassembled, the bores 178 and bores 166 are aligned in a one-to-onerelationship.

With reference to FIGS. 16-20, a plurality of suction plugs 180 arearranged in a one-to-one relationship with the horizontal bore 166formed in the fluid end body 102. Each suction plug 180 seals theopening of its associated horizontal bore 166 at the front surface 176.Likewise, a plurality of discharge plugs 182 are arranged in aone-to-one relationship with the vertical bores 164 formed in the fluidend body 102. Each discharge plug 182 seals the opening of itsassociated vertical bore 164 at the top surface 172. When installed, theplugs 180 and 182 block the flow of fluid through the bore openingsformed in the front and top surface 176 and 172 of the fluid end body102. The plugs 180 and 182 are each preferably made of metal, such ashigh strength steel.

As previously discussed with regard to FIG. 6, the seals 77 installedwithin the plugs 74 and 76 wear against the walls surrounding the bores56 and 58 during operation of traditional fluid ends. Over time, suchwear erodes the walls surrounding the bores 56 and 58, causing fluid toleak around the plugs 74 and 76. The inventors engineered the suctionand discharge plugs 180 and 182 and the fluid end body 102 to minimizesuch erosion.

As also discussed with regard to traditional fluid ends, because theplugs 74 and 76 fit tightly within their corresponding bores 56 and 58,significant forces are required to push or pull the plugs 74 and 76 inand out of the fluid end 46. The inventors engineered the suction anddischarge plugs 180 and 182 used with the fluid end 100 to minimize theamount of torque required during the installation and removal process.

With reference to FIGS. 28-30, each of the suction plugs 180 comprises acylindrical body having opposed top and bottom surfaces 186 and 188. Thesuction plug 180 is substantially solid with the exception of a threadedhole 190 formed in its top surface 186. The suction plug 180 includes anupper portion 192 joined to a lower portion 194 by a tapered portion196.

The lower portion 194 has a reduced diameter relative to that of theupper portion 192. The lower portion 194 also includes a plurality ofsections along its length, the sections have several differentdiameters. The section of greatest diameter is situated midway along thelength of the lower portion 194, and presents an external sealingsurface 198. First and second sections 200 and 202 are formed onopposite sides of the sealing surface 198. Each of the sections 200 and202 has a reduced diameter relative to that of the sealing surface 198.A third section 204 extends between the second section 202 and thebottom surface 188. The third section 204 has a reduced diameterrelative to that of the second section 202.

With reference to FIG. 19, a plurality of beveled corners 206 are formedin the fluid end body 102 at the intersection of the front surface 176and the walls surrounding the opening of each horizontal bore 166. Whena suction plug 180 is installed within one of the horizontal bores 166,the tapered portion 196 of the plug 180 engages the beveled corners 206.Such engagement prevents further axial movement of the plug 180 withinthe bore 166. The upper portion 192 of the plug 180 projects from afront surface 176 of the fluid end body 102 when installed within one ofthe bores 166. In alternative embodiments, the upper portion of thesuction plug may engage the front surface of the fluid end body. Infurther alternative embodiments, axial movement of the suction plugwithin the bore may be prevented by engagement of the bottom surface ofthe plug with the walls surrounding the bore.

Turning back to FIGS. 28-30, the outer surface of the plug 180 includesno annular recess for housing a seal. Instead, an annular recess 208 isformed in the walls surrounding each of the horizontal bores 166adjacent the front surface 176 of the fluid end body 102, as shown inFIGS. 19 and 31. The recess 208 is configured for housing an annularseal 214. Preferably, the seal 214 is a high pressure seal.

With reference to FIG. 31, each recess 208 comprises two sidewalls 210joined by a base 212. The seal 214 is closely received within the recess208. After a seal 214 is installed within a corresponding recess 208within a bore 166, a suction plug 180 is installed within that bore.

When a suction plug 180 is installed within a bore 166, the seal 214within the bore tightly engages the plug's sealing surface 198. Duringoperation, the seal 214 wears against the sealing surface 198 of thesuction plug 180. If the sealing surface 198 on one of the plugs 180begins to erode, allowing fluid to leak around the plug 180, that plug180 is removed and replaced with a new plug. The seal 214 may also beremoved and replaced with a new seal, if needed.

Continuing with FIG. 31, a small amount of clearance exists between thewalls surrounding the bore 166 and the first, second, and third sections200, 202, and 204 of the installed plug 180. The clearance allows thesuction plug 180 to rock back and forth on each side of its sealingsurface 198. The rocking motion helps to overcome friction between eachof the plugs 180 and the walls surrounding its corresponding bore 166.Thus, less force is required for installation or removal of one of theplugs 180 than is required for a traditional suction plug. Lessortorques mean fewer scrapes and scratches on the walls surrounding thebore, as compared to a traditional suction plug.

The suction plugs 180 may be installed and removed using a tool (notshown), which may be attached to a plug 180 at the threaded hole 190,shown in FIG. 19. For example, a tool having an externally threaded endmay mate with the internal threads formed in the threaded hole 190. Onceinstalled, an operator may rock the plug 180 back and forth using thetool while simultaneously pushing or pulling on the plug 180 with thetool.

Turning to FIGS. 32-34, each of the discharge plugs 182 comprises acylindrical body having opposed top and bottom surfaces 216 and 218. Thedischarge plug 182 is substantially solid with the exception of twothreaded holes. A first threaded hole 220 formed in its top surface 216and a second threaded hole 222 formed in its bottom surface 218. Eachplug 182 includes an upper portion 224 joined to a lower portion 226 bya tapered portion 228.

The lower portion 226 includes a plurality of sections along its length,the sections have several different diameters. The section of thegreatest diameter is situated midway along the length of the lowerportion 226, and presents an external sealing surface 230. First andsecond sections 232 and 234 are formed on opposite sides of the sealingsurface 230. Each of the sections 232 and 234 has a reduced diameterrelative to that of the sealing surface 230. A third section 236 isformed below the second section 234 and has a reduced diameter relativeto that of the second section 234. The third section 236 includes aplurality of reduced diameter sections.

Each plug 182 further includes a connection portion 238. The connectionportion 238 extends between the third section 236 and the bottom surface218. The connection portion 238 has a reduced diameter relative to thatof the lower portion 226. The second threaded hole 222 extends withinthe connection portion 238. As will be described later herein, theconnection portion 238 is configured for connecting to a spring 438 usedwith a discharge valve 402, shown in FIGS. 18 and 24.

With reference to FIG. 20, a plurality of bevelled corners 244 areformed in the fluid end body 102 at the intersection of the top surface172 and the walls surrounding the opening of each vertical bore 164.When a discharge plug 182 is installed within one of the vertical bores164, the tapered portion 228 of the plug 182 engages the beveled corners244. Such engagement prevents further axial movement of the plug 182within the bore 164. The upper portion 224 of the plug 182 projects fromthe top surface 172 of the fluid end body 102 when installed within oneof the bores 164. In alternative embodiments, the upper portion of thedischarge plug may engage the top surface of the fluid end body. Infurther alternative embodiments, axial movement of the discharge plugwithin the bore may be prevented by engagement of the bottom surface ofthe plug with the walls surrounding the bore.

Turning back to FIGS. 32-34, the outer surface of the plug 182 includesno annular recess for housing a seal. Instead, an annular recess 246 isformed in the walls surrounding each of the vertical bores 164 adjacentthe top surface 172 of the fluid end body 102, as shown in FIGS. 20 and35. The recess 246 is configured for housing an annular seal 252.Preferably, the seal 252 is a high pressure seal.

With reference to FIG. 35, each recess 246 comprises two sidewalls 248joined by a base 250. The seal 252 is closely received within the recess246. After a seal 252 is installed within a corresponding recess 246within a bore 164, a discharge plug 182 is installed within that bore.

When a discharge plug 182 is installed within a bore 164, the seal 252tightly engages the plug's sealing surface 230. During operation, theseal 252 wears against the sealing surface 230 of the discharge plug182. If the sealing surface 230 on one of the plugs 182 begins to erode,allowing fluid to leak around the plug 182, that plug 182 is removed andreplaced with a new plug. The seal 252 may also be removed and replacedwith a new seal, if needed.

Continuing with FIG. 35, a small amount of clearance exists between thewalls surrounding the bore 164 and the first, second, and third sections232, 234, and 236 of the installed plug 182. The clearance allows thedischarge plug 182 to rock back and forth on each side of its sealingsurface 230. The rocking motion helps to overcome friction between eachof the plugs 182 and the walls surrounding its corresponding bore 164.The discharge plugs 182 may be installed and removed using a tool (notshown), which may be attached to a plug 182 at the threaded hole 220,shown in FIG. 20.

In alternative embodiments, the suction and discharge plugs may beformed in accordance with those embodiments described in Appendices A,G, and I.

With reference to FIGS. 19 and 20, when the fluid end 100 is operating,the bottom surfaces 188 and 218 of each of the plugs 180 and 182 will beexposed to the high fluid pressures within the interior of the fluid end100. The fluid pressure may be high enough to dislodge the suction anddischarge plugs 180 and 182 from their respective bores 166 and 164. Tokeep the plugs 180 and 182 within their respective bores 166 and 164, aplurality of retainers 254 are attached to the fluid end body 102. Aretainer 254 is attached to the body 102 above each of the plugs 180 and182, as shown in FIG. 9.

As previously discussed with regard to FIG. 6, traditional retainers 78are threaded into the walls surrounding each of the bores 56 and 58immediately above the plugs 74 and 76. Significant levels of torque canbe required to thread and unthread a retainer 78 from a fluid end 46.Such torques can lead to cracking of threads and fluid end failure. Theinventors engineered the retainers 254 used with the fluid end 100 toreduce such failures.

With reference to FIG. 36, each retainer 254 has a cylindrical bodyhaving flat opposing top and bottom surfaces 256 and 258. A threadedcentral passage 260 is formed in the center of each of retainer 254. Thecentral passage 260 interconnects the top and bottom surfaces 256 and258. A plurality of peripheral passages 264 are formed in each retainer254 and surround the central passage 260. Each peripheral passage 264interconnects the top and bottom surfaces 256 and 258 of each retainer254.

With reference to FIGS. 25, 26, 37, and 38, a retainer nut 262 isinstalled within the central passage 260 of each retainer 254, as shownin FIGS. 25 and 26. A central passage 280 is formed in the retainer nut262. The central passage 280 interconnects the nut's top and bottomsurfaces 282 and 284. External threads are formed on the retainer nut262 adjacent its bottom surface 284. The external threads are matinglyengageable with the internal threads formed in the retainer 254, asshown in FIGS. 25 and 26. The walls surrounding the central passage 280adjacent the top surface 282 of the retainer nut 262 are shaped toclosely receive a hex-shaped tool.

With reference to FIGS. 16, 17, 25, and 26, a plurality of peripheralopenings 266 are formed in the fluid end body 102 around each opening ofeach vertical and horizontal bore 164 and 166. The peripheral passages264 formed in each retainer 254 are alignable with the peripheralopenings 266 formed around each of the bores 164 and 166, in aone-to-one relationship.

Each of the retainers 254 is secured to the fluid end body 102 using afastening system 268, as shown in FIGS. 16 and 17. The fastening system268 comprises a plurality of studs 270, a plurality of washers 272, anda plurality of nuts 274. Each stud 270 is externally threaded adjacentits first end 276, while each peripheral opening 266 formed in the fluidend body 102 has internal threads that mate with those of the stud 270,as shown in FIGS. 25 and 26. Studs 270 are threaded into place withineach of the peripheral openings 266 within which a retainer 254 isaligned.

Continuing with FIGS. 25 and 26, once a first stud 270 has beeninstalled in the fluid end body 102 at its first end 276, its opposedsecond end 278 projects from the body's top or front surface 172 or 176.Each peripheral passage 264 formed in each of the retainers 254 receivesa corresponding one of the studs 270. Each of the studs 270 receives awasher 272 and nut 274, which hold the retainer 254 against the top andfront surface 172 and 176 of the fluid end body 102. Rather thanapplying a single large torque to a single retainer, the fasteningsystem 268 contemplates distribution of smaller torques among aplurality of studs 270 and nuts 274.

When a retainer 254 is attached to the fluid end body 102, the centralpassage 260 surrounds the upper portion 192 or 224 of the plug 180 or182. The retainer nut 262 installed within the retainer 254 is torquedso that its bottom surface 284 tightly engages with the top surface 186or 216 of the plug 180 or 182. Such engagement maintains the plug 180 or182 within its corresponding bore 166 or 164. When the retainer nut 262is engaged with the top surface 186 or 216 of the plug 180 or 182, thethreaded hole 190 or 220 formed in the plug 180 or 182 is exposed to thenut's central passage 280.

During operation, an operator may need access to the inside of the fluidend 100 multiple times during a single fracking operation. For example,one of the plugs 180 or 182 may need to be replaced. Removing a retainer254 to gain such access can be time-consuming, because of the need toremove multiple nuts 274 and washers 272.

To avoid such delays, each retainer 254 includes a removable retainernut 262. Rather than remove all of the nuts 274 and washers 272, theoperator can simply remove the retainer nut 262. When the retainer nut262 is removed, the operator can access the interior of the fluid endbody 102 through the central opening 260 of the retainer 254. Theretainer nut 262 may be removed using a hex-shaped tool that mates withthe walls surrounding the central passage 280 of the retainer nut 262.

While the fluid end 100 includes a plurality of threaded retainer nuts262, those retainer nuts 262 are not threaded into the walls surroundingthe bores 164 and 166. Thus, even if the threads on one of retainer nuts262 should crack, the fluid end body 102 remains intact. Only theretainer nut 262 and/or its corresponding retainer 254 need be replaced.The high cost of repairing or replacing the fluid end body 102 isthereby avoided.

Turning to FIG. 39, one of the studs 270 used with the fastening system268 is shown. The stud 270 has a first threaded section 286 and anopposite second threaded section 288. The threaded sections 286 and 288are joined by an elongate body 290. The first threaded section 286 isconfigured for threading into one of the plurality of threaded openings266 formed in the fluid end body 102. The second threaded section 288 isconfigured for threading into the threaded opening formed in one of thenuts 274.

The first section 286 may have fewer threads than that of itscorresponding opening 266. For example, if the opening 266 has eighteen(18) internal threads, the first section 286 may only have sixteen (16)external threads. This configuration ensures that all of the threadsformed on the first section 286 will be engaged and loaded when thefirst section 286 is threaded into one of the openings 266. Engaging allof the threads helps to increase the fatigue life of the first section286 of each stud 270. Each stud 270 may also be subjected to shotpeening on its non-threaded sections prior to its use to help reduce thepossibility of fatigue cracks. Each stud 270 may have a smooth outersurface prior to performing shot peening operations.

Continuing with FIG. 39, the body 290 of each stud 270 comprises anenlarged portion 292 joined to a constricted portion 294. The enlargedportion 292 is positioned adjacent the second section 288, whichreceives one of the washers 272 and nuts 274. The enlarged portion 292has a greater diameter than the lower portion 294.

The diameter of the enlarged portion 294 is only slightly smaller thanthe diameter of the central opening of each washer 272. This sizingallows each washer 272 to closely receive the upper portion 294 of eachstud 270. Such engagement operates to center the washer 272 on the stud270 and center the washer 272 relative to each nut 274. Otherwise, thewasher 272 must be manually centered on the stud 270 and nut 274, whichcan be difficult. If the washer 272 is not properly centered, it may bedifficult to effectively torque or un-torque the nut 274 from thecorresponding stud 270.

The plurality of washers 272 used with the fastening system 268 may beconfigured to allow a large amount of torque to be imposed on the nuts274 without using a reaction arm. Instead, the washer 272 itself mayserve as the counterforce needed to torque a nut 274 onto a stud 270.Dispensing with a reaction arm increases the safety of the assemblyprocess. The nuts 274 used with the fastening systems 268 may alsocomprise a hardened inner layer to help reduce galling between thethreads of the nuts and studs during the assembly process.

In alternative embodiments, the retainers and corresponding fasteningsystem may be constructed like those embodiments described in AppendixA.

Continuing with FIGS. 18 and 24, when the connect plate 104 is attachedto the fluid end body 102, the horizontal bores 178 formed in theconnect plate 104 serve as extensions of the horizontal bores 166 formedin the fluid end body 102. Each pair of aligned bores 166 and 178receives a single plunger 296, as shown in FIG. 10. Each plunger 296extends through a pair of horizontal bores 166 and 178 and into itsassociated internal chamber 168. Like traditional fluid ends, each ofthe plungers 296 is attached to a pony rod 44 included in the power end34 in a one-to-one relationship, as shown in FIGS. 7 and 8.Reciprocation of the pony rods 44 reciprocates the plungers 296 withinthe interior of the fluid end 100.

As previously discussed with regard to FIG. 6, each plunger 52 isinstalled within a plurality of packing seals 64 in traditional fluidends. Over time, the seals 64 erode the walls surrounding the bore 58.To combat such erosion, the inventors engineered a stuffing box sleeve298 to be installed within each bore 58. The sleeve 298 is configured tohouse a plunger packing 368. The plunger packing 368 comprises aplurality of packing seals 370 and 372. Over time, the seals 370 and 372wear against the inner surface of the sleeve 298. If leakage occurs, thesleeve 298 may be removed and replaced with a new sleeve. As discussedbelow, the sleeve 298 was further engineered to combat additional pointsof erosion.

As also previously discussed with regard to FIG. 6, the threadedretainers 65 used with the packing seals 64 are prone to threadcracking, leading to fluid end failures. The inventors engineered thestuffing box sleeves 298 and their corresponding retainers 300 to reducesuch failures.

With reference to FIGS. 40-43, each of the stuffing box sleeves 298 hasa central passage 318 that opens on the sleeve's opposed top and bottomsurfaces 302 and 304. Each sleeve 298 includes a cylindrical lowerportion 306 joined to cylindrical upper portion 308 by a tapered portion310. An annular internal seat 312 is formed in the walls surrounding thecentral passage 318 adjacent the tapered portion 310.

The lower portion 306 has a reduced diameter relative to that of theupper portion 308. A flange 314 is formed around the upper portion 308and serves as an extension of the top surface 302. A plurality ofperipheral passages 316 are formed within the flange 314 and surroundthe central passages 318. Each of the peripheral passages 316interconnects the sleeve's top surface 302 and a bottom surface 320 ofthe flange 314. The sleeves 298 are each preferably made of metal, suchas high strength steel.

With reference to FIG. 21, a plurality of beveled corners 322 are formedin the fluid end body 102 at the intersection of the opening of thehorizontal bore 166 and the rear surface 106 of the fluid end body 102.When each sleeve 298 is installed within one of the horizontal bores166, the sleeve's tapered portion 310 engages the beveled corners 322.Such engagement prevents further axial movement of each sleeve 298within its corresponding bore 166.

With reference to FIG. 27, a counterbore 324 is formed in each of thebores 178 in the connect plate 104 adjacent the plate's rear surface124. A plurality of threaded peripheral openings 326 are formed within abase 328 of each counterbore 324. The peripheral openings 326 extendinto connect plate 104. When each of the sleeves 298 is installed withinone of the bores 178, the bottom surface 320 of the sleeve's flange 314engages with the base 328 of the counterbore 324, as shown in FIG. 21.Each of the peripheral passages 316 formed in the flange 314 align withone of the peripheral openings 326 formed in the base 328 in aone-to-one relationship.

Turning back to FIGS. 40-43, the outer surface of the sleeve 298includes no annular recess for housing a seal. Instead, an annularrecess 330 is formed in the walls surrounding each of the horizontalbores 166 adjacent the rear surface 106 of the fluid end body 102, asshown in FIGS. 21 and 27. The recess 330 is configured to housing anannular seal 336. Preferably, the seal 336 is a high pressure seal.

Continuing with FIG. 21, each recess 330 comprises two sidewalls 332joined by a base 334. The seal 336 is closely received within the recess330. After a seal 336 is installed within a recess 330 within one of thebores 166, a sleeve 298 is installed within that bore.

When a sleeve 298 is installed within a bore 166, the seal 336 withinthe bore tightly engages the outer surface of the sleeve's lower portion306. During operation, the seal 336 wears against the lower portion 306.If the outer surface of the lower portion 306 begins to erode, allowingfluid to leak around the sleeve 298, that sleeve 298 is removed andreplaced with a new sleeve. The seal 336 may also be removed andreplaced with a new seal, if needed.

Continuing with FIGS. 21 and 27, the bottom surfaces 304 of the sleeves298 will be exposed to high fluid pressure within the interior of thefluid end 100. The fluid pressure may be high enough to dislodge asleeve 298 from its corresponding aligned bores 166 and 178. To keep thesleeves within their corresponding bores 166 and 178, a plurality ofretainers 300 are attached to the connect plate 104 above each sleeve298, as shown in FIG. 10.

With reference to FIGS. 44 and 45, each of the retainers 300 has acylindrical body having opposed top and bottom surfaces 338 and 340. Acentral passage 342 is formed in the interior of each retainer 300.Internal threads 344 are formed in the walls surrounding the centralpassage 342 adjacent the retainer's top surface 338. A counterbore 346is formed in the central passage 342 adjacent the retainer's bottomsurface 340. A plurality of peripheral passages 348 are formed in eachretainer 300 and surround each central passage 342. Each peripheralpassage 348 interconnects the retainer's top surface 338 and a base 350of each counterbore 346. The retainers 300 are each preferably made ofmetal, such as high strength steel.

A plurality of annular recesses are formed in the outer surface of eachretainer 300 adjacent its bottom surface 340. A first and a thirdannular recess 352 and 354 are each configured for housing a seal 357,shown in FIG. 21. Preferably, the seal 357 is an O-ring. The first andthird recesses 352 and 354 are formed on opposite sides of a secondannular recess 356. A plurality of passages 358 are formed in the secondannular recess 356. The passages 358 interconnect the inner and outersurfaces of the retainer 300.

With reference to FIG. 27, each retainer 300 is sized to be closelyreceived within one of the counterbores 324 in the connect plate 104, ina one-to-one relationship. When each retainer 300 is installed withinthe connect plate 104, the bottom surface 340 of each retainer 300engages the base 328 of each counterbore 324. Each sleeve's flange 314is sized to be closely received within each counterbore 346 formed ineach retainer 300. When assembled, the top surface 302 of each sleeve300 engages with the base 350 of each counterbore 346.

Each of the retainers 300 is secured to the connect plate 104 using afastening system 360, shown in FIGS. 16 and 17. The fastening system 360comprises a plurality of threaded screws 362. The screws 362 arepreferably socket-headed cap screws. Each of the screws 362 is receivedwithin one of the openings 326 formed in each counterbore's base 328,one of the passages 316 formed in each flange 314, and one of thepassages 348 formed in each retainer 300, in a one-to-one relationship.

The screws 362 are rotated until they tightly attach each of theretainers 300 to the connect plate 104 and securely hold each sleeve 298within each set of aligned bores 166 and 178. Because each of theretainers 300 is attached to the connect plate 104 using the fasteningsystem 360, no external threads are formed on the outer surface of eachretainer 300. Likewise, no internal threads are formed within the wallsof each pair of aligned horizontal bores 166 and 178.

Turning back to FIG. 21, when a retainer 300 is installed within one ofthe counterbores 324, the retainer's second annular recess 356 alignswith a weep hole 364 formed in the connect plate 104. The weep hole 364is a bore that interconnects a top surface 366 of the connect plate 104and one of the counterbores 324. A plurality of weep holes 364 areformed in the connect plate 104, as shown in FIG. 10. Each weep hole 364opens into one of the counterbores 324 in a one-to-one relationship.

During operation, small amounts of fluid may leak around each of theplungers 296, the seal 336 or the plunger packing 368. The fluid maypass through the openings 358 in each retainer 300 and into the secondannular recess 356. From the second annular recess 356, the fluid mayflow into the corresponding weep hole 364 and eventually exit the fluidend 100. Thus, each second annular recess 356 and each correspondingweep hole 364 serve as a fluid flow path for excess fluid to exit thefluid end 100.

Prior to installing a plunger 296 within one of the sleeves 298, theplunger packing 368, shown in FIGS. 16 and 17, is installed withincentral passage 318 of the sleeve 298, as shown in FIG. 21. The plungerpacking 368 prevents high pressure fluid from passing around the plunger296 as the plunger reciprocates. Each plunger packing 368 comprises aplurality of annular seals compressed together and having alignedcentral passages. The outer seals 370 may be made of metal and compressthe inner pressure seals 372, as shown in FIG. 21. The inner pressureseals 372 are preferably high pressure seals.

With reference to FIGS. 21 and 27, when a plunger packing 368 isinstalled within a sleeve 298, one of the outer seals 370 engages thesleeve's internal seat 312. The plunger packing 368 is secured withinthe sleeve 298 by a packing nut 374.

With reference to FIGS. 46 and 47, each packing nut 374 comprises acylindrical body having a central passage 380 formed therein. Thecentral passage 380 interconnects the packing nut's top and bottomsurfaces 376 and 378. An annular recess 382 is formed within the wallssurrounding the central passage 380 and houses a seal 384, as shown inFIG. 21. Preferably, the seal 384 is a lip seal. The seal 384 helpsprevent fluid from leaking around the packing nut 374 during operation.The outer surface of each packing nut 374 is threaded adjacent itsbottom surface 378. The external threads on each packing nut 374 arematingly engageable with the internal threads formed in each retainer300. The packings nuts 374 are each preferably made of metal, such ashigh strength steel.

Turning back to FIGS. 21 and 27, when a packing nut 374 is installedwithin one of the retainers 300, the bottom surface 378 of the packingnut 374 engages with one of the outer seals 370 of the plunger packing368. Such engagement compresses the plunger packing 368, creating atight seal. When installed within the retainer 300, the packing nut'scentral passage 380 aligns with the central passages formed in eachplunger packing 368.

A plurality of peripheral passages 369 are formed in the outer surfaceof each packing nut 374 adjacent its top surface 376. The passages 369interconnect central passage 380 and the outer surface of each packingnut 374. The passages 369 serve as connection points for a spannerwrench. When assembling the fluid end 100, the spanner wrench is used totightly thread each packing nut 374 into its corresponding retainer 300.

Once a sleeve 298, plunger packing 368, retainer 300, and packing nut374 are installed within a pair of aligned horizontal bores 166 and 178,a plunger 296 is then installed within those bores. Alternatively, theplunger 296 may be installed prior to installing the packing nut 374.When a plunger 296 is installed within the fluid end 100, the componentsinstalled within each pair of aligned bores 166 and 178 surround theouter surface of the plunger 296. During operation, the plunger 296moves relative to the fluid end 100 and the components installed withinthe aligned bores 166 and 178.

With reference to FIG. 18, each of the plungers 296 is preferably madeof metal, such as high strength steel, and comprises an elongatecylindrical body 388 having opposed first and second ends 390 and 392.The first end 390 of each plunger 296 is flat and a flange 394 ismachined into the second end 392 of each plunger 296. The flange 394 isconfigured to receive a clamp 396. The clamp 396 is used to secure eachplunger 296 to one of the pony rods 44 included in the power end 34, asshown in FIGS. 7 and 8. As each plunger 296 reciprocates, the effectivevolume of fluid within each corresponding internal chamber 168continually changes. Force applied to the fluid by each plunger 296pressurizes the fluid.

In alternative embodiments, the components installed within the fluidend and surrounding the plunger may be constructed like thoseembodiments described in Appendix A.

Continuing with FIGS. 18 and 24, an intake and discharge valve 400 and402 are installed within each vertical bore 164 on opposite sides of theinternal chamber 168. The intake valve 400 prevents backflow in thedirection of a manifold 103, shown in FIGS. 7 and 8. The discharge valve402 prevents backflow in the direction of the internal chamber 168. Thevalves 400 and 402 each comprise a valve body 406 that seals against avalve seat 404.

As previously discussed with regard to FIG. 6, a corner 99 is formed inthe walls surrounding the vertical bore 56 adjacent the valve seats 89in a traditional fluid end. The corner 99 is configured for engagingwith the upper flange 96 formed on the each valve seat 89. Duringoperation, the corners 99 are prone to fatigue cracks. The inventorsengineered the valve seats 404 and the walls of the fluid end 100surrounding the valve seats 404 to combat such failures.

With reference to FIGS. 48-51, each of the valve seats 404 is preferablymade of metal, such as high strength steel, and has a cylindrical bodyhaving a central passage 412 formed therein. The central passage 412interconnects the seat's top and bottom surfaces 408 and 410. When avalve seat 404 installed within one of the vertical bores 164, theseat's central passage 412 is in fluid communication with the bore 164.

An upper flange is not formed on the valve seat 404. Instead, the outersurface of the valve seat 404 has an upper section 411 that joins atapered section 414. The tapered section 414 is formed between the uppersection 411 and the seat's bottom surface 410. The upper section 411 hasa uniform diameter with the exception of an annular recess 416. Theannular recess 416 is configured to house a seal 418, as shown in FIG.18. Preferably, the seal 418 is an O-ring. The seal 418 helps preventfluid from leaking between the outer surface of the valve seat 404 andthe walls surrounding the vertical bore 164.

With reference to FIGS. 22 and 23, a taper 420 corresponding with thetaper 414 is formed in the walls surrounding each vertical bore 164adjacent each valve seat 404. When a valve seat 404 is installed withinone of the bores 164, the corresponding tapers 420 and 414 engage andprevent further axial movement of the valve seat 404 within the bore164.

In contrast to the corner 99 formed in the walls of the fluid end 46,shown in FIG. 6, the angle α of the taper 420 is greater than 180degrees, as shown in FIG. 22. Increasing the size of the angle αsignificantly decreases the stress concentrations applied to the wallsof each vertical bore 164 during operation, thereby increasing the lifeof the fluid end 100.

As previously discussed with regard to FIG. 6, during operation of thefluid end 46, the sealing surface on the valve seat 86 may wear andeventually erode, allowing the valves to leak. The inventors engineeredthe valve seats 404 to combat such erosion.

Turning back to FIGS. 48-51, an annular recess 422 is formed in the topsurface 408 of each valve seat 404. The location of the recess 422corresponds with the area of the valve seat 404 known to erode overtime. The recess 422 is configured for housing a hardened insert 424.The insert 424 is preferably made of a hardened material, such astungsten carbide. Such material resists wear and erosion, significantlyextending the life of the valve seat 404. The insert 424 is sized to beclosely received with the recess 422. The top surface of the insert 424is characterized by a taper 425.

With reference to FIGS. 52-54, each valve body 406 is preferably made ofmetal, such as high strength steel, and has a cylindrical body havingopposed top and bottom surfaces 428 and 430. A sealing surface 426 isformed on the bottom surface 430 of each valve body 406. The sealingsurface 426 is characterized by a taper that corresponds with the taper425 formed in the top surface of the insert 424. During operation, thesealing surface 426 engages the insert's taper 425, as shown in FIGS. 22and 23. Such engagement blocks the flow of fluid around the valve body406.

Each valve body 406 further includes an upper spring connection 432projecting from its top surface 428 and a lower aligning element 434projecting from its bottom surface 430. Each lower aligning element 434comprises a plurality of downwardly extending legs 436. In operation,the legs 436 engage with the interior walls of each valve seat 404 andhelp ensure proper alignment of the sealing element 426 with the topsurface 408 of the valve seat 404.

Each valve body 406 is held against a corresponding valve seat 404 by aspring 438, shown in FIGS. 22 and 23. Each spring connection 432 isconfigured to attach to a first end 440 of one of the springs 438. Eachspring connection 432 also includes a flat retaining surface 442.

Continuing with FIG. 23, a valve retainer 446 is installed within thewalls surrounding the bores 164 above each intake valve 400. The valveretainer 446 is a U-shaped piece that extends the width of the verticalbore 164. Opposed ends of the valve retainer 446 are positioned withinrecesses formed in the walls surrounding each bore 164. A flat retainingsurface 448 is formed at the apex of the valve retainer 446 on itsbottom surface. The retaining surface 448 is aligned with the retainingsurface 442 formed in the spring connection 432. A second end 444 ofeach spring 438 is attached to one of the valve retainers 446.

In operation, the spring 438 holds the valve body 406 against the valveseat 404. Fluid pressure applied to the bottom surface 430 of the valvebody 406, forces the valve body 406 to move upwards, compressing thespring 438. As the valve body 406 moves upwards, further movement of thevalve body 406 is prevented by the engagement of the retaining surfaces448 and 442.

With reference to FIG. 22, the second end 444 of the spring 438 usedwith one of the discharge valves 402 is attached to the springconnection portion 238 of each discharge plug 182. As the dischargevalve's valve body 406 moves upwards, further movement of the valve body406 is prevented by the engagement of the retaining surface 442 with thebottom surface 218 of the discharge plug 182.

Turning back to FIGS. 7 and 8, during operation, fluid is delivered tothe fluid end 100 through the manifold 103. The manifold 103 is attachedto the bottom surface 174 of the fluid end body 102 and is in fluidcommunication with each of the vertical bores 164. As each of theplungers 296 reciprocates within the fluid end 100, fluid is drawn fromthe manifold 103 into each of the internal chambers 168 as the intakevalves 400 repeatedly open and close.

Pressurized fluid is forced into a discharge conduit 105, shown in FIGS.18 and 24, as the discharge valves 402 repeatedly open and close. Fluidexits the fluid end 100 through one or more discharge openings 107,which are in fluid communication with the discharge conduit 105. Thefluid end 100 may be attached to intake and discharge piping systems,like those shown in FIG. 2.

In some fluid ends, the vertical bore may be longer than that shown inFIGS. 18 and 24. In such case, the spring 438 may not span the distancebetween the valve body 406 and the bottom surface 218 of the dischargeplug 182. A valve retainer 450 may be used to decrease the distancebetween the valve body 406 and the plug 182, as shown in FIG. 70.

Continuing with FIG. 70, each valve retainer 450 comprises an elongatebody. A bottom surface of the elongate body is characterized by a springconnection portion 451 and a retaining surface 452. A top surface of theelongate body is installed in the second threaded hole 222 formed in theconnection portion 238 of one of the discharge plugs 182. Wheninstalled, the valve retainer 450 extends downwards towards itscorresponding valve body 406. The second end 444 of the spring 438 isattached to the retainer's spring connection portion 451. As thedischarge valve's valve body 406 moves upwards, further movement of thevalve body 406 is prevented by the engagement of the retaining surfaces448 and 452.

In alternative embodiments, the intake and discharge valves may beconstructed like those embodiments described in Appendices B, C, D, E,and F.

Continuing with FIGS. 7-27, with regards to manufacturing the fluid end100, after the fluid end body 102 and connect plate 104 are formed, thebores and openings described herein are machined into the fluid end body102 and the connect plate 104. The studs 138 as well as the internalcomponents shown in FIGS. 18 and 24, including the valves 400 and 402,springs 438, valve retainers 446, seals 214, 252 and 336, plugs 180 and182, retainers 254 and fastening system 268 are next installed in thefluid end body 102. After the necessary bores have been formed in theconnect plate 104, the stuffing box sleeves 298, retainers 300, plungerpackings 368, packing nuts 374 fastening system 360, and plungers 296described herein are installed. Prior to operation, the connect plate104 is attached to the power end 34, and the fluid end body 102 isattached to the connect plate 104.

Turning now to FIGS. 55-58, an alternative embodiment of a fluid end 500is shown. The fluid end 500 may be used with the same power end 34 shownin FIGS. 7 and 8. The fluid end 500 comprises a fluid end body 502releasably attached to a connect plate 504. The fluid end body 502 isattached to the connect plate 504 in the same manner as the fluid endbody 102 and the connect plate 104 shown in FIGS. 7-11. Except asdescribed hereafter, the fluid end 500 is identical to the fluid end100. A removable stuffing box sleeve 506 installed within the fluid end500 has a different shape than the sleeve 298 installed within the fluidend 100. As a result, the areas of the fluid end body 502 and connectplate 504 that receive the sleeve 506 have a different shape than thoseareas in the fluid end body 102 and connect plate 104.

With reference to FIGS. 59 and 60, a plurality of longitudinally spacedhorizontal bores 508 are formed in the fluid end body 502. The bores 508interconnect opposed front and rear surfaces 505 and 507 of the fluidend body 502. Each bore 508 includes a counterbore 510, as also shown inFIG. 58. Each counterbore 510 has a base 512 and opens on the rearsurface 507 of the fluid end body 502. A plurality of internallythreaded peripheral openings 516 are formed in the base 512, as shown inFIGS. 58 and 60. The openings 516 surround the bores 508 and extend intothe fluid end body 502.

A plurality of longitudinally spaced horizontal bores 518 are formed inthe connect plate 504, as shown in FIG. 58. The bores 518 interconnectthe front and rear surfaces 520 and 522 of the connect plate 504. Thebores 518 do not include any counterbores. Instead, each bore 518 has agenerally uniform diameter between the front and rear surfaces 520 and522. The diameter of each bore 518 matches with the diameter of eachcounterbore 510 formed in the fluid end body 502, as shown in FIGS. 59and 60. When the fluid end 500 is assembled, the counterbores 510 andbores 518 align in a one-to-one relationship.

With reference to FIGS. 61 and 62, the sleeve 506 has a cylindricallower portion 524 joined to a cylindrical upper portion 526. The lowerportion 524 has a lesser diameter than that of the upper portion 526.Unlike the sleeve 298 shown in FIGS. 40-43, the sleeve 506 does notinclude a tapered portion. Instead, the lower portion 524 is joineddirectly to a bottom surface 528 of the upper portion 526. A centralpassage 530 extends through the sleeve 506 and interconnects thesleeve's top and bottom surfaces 532 and 534. An internal seat 536 isformed in the walls surrounding the central passage 530 adjacent thebottom surface 528 of the upper portion 526, as shown in FIG. 59.

Unlike the sleeve 298 shown in FIGS. 40-43, the upper portion 526 doesnot include a flange. Instead, the upper portion 526 has a generallyuniform outside diameter along its length. A plurality of peripheralpassages 538 are formed in the upper portion 526 and surround thecentral passage 530. The passages 538 interconnect the sleeve's topsurface 532 and the bottom surface 528 of the upper portion 526.

A plurality of threaded openings 540 are formed in the top surface 532of the sleeve 506. The threaded openings 540 allow use of a tool forgripping the sleeve 506 while it is being installed or removed.

Turning back to FIG. 59, the upper portion 526 of the sleeve 506 has agreater length than the upper portion 308 formed in the sleeve 298. Whenthe sleeve 506 is installed within the fluid end 500, a weep hole 542formed in the connect plate 504 faces the sleeve 506. In contrast, inthe fluid end 100, with its shorter sleeve 298, the weep hole 364 facesthe retainer 300.

Because of the alignment between the weep hole 542 and the sleeve 506,first, second, and third annular recess 546, 548, and 550 are formed inan outer surface of the sleeve 506, as shown in FIGS. 61 and 62. Each ofthe first and third recesses 546 and 550 are configured to house a seal552, as shown in FIG. 59. Preferably, the seal 552 is an O-ring. Thesecond recess 548 underlies the weep hole 542, and is interconnectedwith the sleeve's central passage 530 by a plurality of spaced passages554. Any fluid leaking around the sleeve 506 flows from the centralpassage 530, through the passages 554, into the second recess 548, andthen into the weep hole 542.

Turning back to FIGS. 61 and 62, the outer surface of the sleeve 506includes no annular recess for housing a high pressure seal. Instead, anannular recess 556, configured to house an annular seal 558, is formedin the walls surrounding each bore 508 adjacent each counterbore 510, asshown in FIG. 59. Preferably, the seal 558 is a high pressure seal.

Continuing with FIG. 59, each recess 556 is identical to the recess 330shown in FIG. 21. The seal 558 is closely received within the recess556. After a seal 558 is installed within a recess 556 within one of thebores 508, a sleeve 506 is installed within that bore.

When a sleeve 506 is installed within a bore 508, the seal 558 withinthe bore tightly engages the outer surface of the sleeve's lower portion524. During operation, the seal 558 wears against the lower portion 524.If the outer surface of the lower portion 524 begins to erode, allowingfluid to leak around the sleeve 506, that sleeve 506 can be removed andreplaced with a new sleeve. The seal 558 may also be removed andreplaced with a new seal, if needed.

Continuing with FIG. 59, when a sleeve 506 is installed within thealigned bores 508 and 518, the bottom surface 528 of the upper portion526 engages the base 512 of the counterbore 510. Such engagementprevents further movement of the sleeve 506 within the fluid end body502. The sleeve 506 is positioned within the aligned bores 508 and 518such that its peripheral passages 538 and the peripheral openings 516formed in the base 512 are aligned in a one-to-one relationship, asshown in FIG. 60.

With reference to FIGS. 63 and 64, a retainer 544 prevents the sleeve506 from being dislodged from the aligned bores 508 and 518. Theretainer 544 comprises a cylindrical body having an internally threadedcentral passage 556. The central passage 556 interconnects theretainer's top and bottom surfaces 558 and 560. A plurality ofperipheral passages 562 surround the central passage 556 andinterconnect the retainer's top and bottom surfaces 558 and 560. Acounterbore 563 is formed within each passage 562, adjacent the topsurface 558 of the retainer 544.

With reference to FIG. 60, the retainer 544 is installed within thecounterbore 510 so that its bottom surface 560 engages the top surface532 of the sleeve 506. The retainer 544 is installed over the sleeve 506such that the peripheral passages 562 and the peripheral passages 538are aligned in a one-to-one relationship.

Unlike the fluid end 100, each of the retainers 544 is secured to thefluid end body 502, instead of to the connect plate 504. Each of theretainers 544 is secured using a fastening system 562 shown in FIGS. 57and 58. The fastening system 562 comprises a plurality of studs 564 anda plurality of nuts 565. Each of the studs 564 is received within acorresponding one of the openings 516 formed in the base 512. From thebase 512, each stud 564 extends through a corresponding one of thepassages 538 in the sleeve 506, and through a corresponding one of thepassages 562 in the retainer 544.

A first end 567 of each stud 564 is positioned within one of thecounterbores 563 formed in the retainer 544. A nut 565 is then placed onthe end 567 of each stud 564, and turned until it tightly engages thebase of the counterbore 563. In alternative embodiments, the fasteningsystem may comprise a plurality of screws instead of studs and nuts. Thescrews are preferably socket-headed cap screws.

Attaching the retainer 544 to the fluid end body 502 also helps ensurethe sleeve 506 remains tightly in place during operation. Because eachof the retainers 544 is attached to the fluid end body 502 using thefastening system 562, no external threads are formed on the outersurface of each of the retainer 544. Likewise, no internal threads areformed within the walls of each set of aligned bores 508 and 518.

Continuing with FIG. 59, a plunger packing 566 is installed within thecentral passage 530 of each sleeve 506. When installed the plungerpacking 566 engages the sleeve's internal seat 536. The plunger packing566 is identical to the plunger packing 368, shown in FIG. 21.

The plunger packing 566 is held within the sleeve 506 by a packing nut568. The packing nut 568 is generally identical to the packing nut 374shown in FIGS. 46 and 47. However, the packing nut 568 may vary slightlyin size from the packing nut 374 in order to properly fit within theretainer 544 and sleeve 506. External threads formed on the outersurface of the packing nut 568 matingly engage the internal threadsformed in the retainer 544.

When a packing nut 568 is installed within one of the retainers 544, abottom surface 378 of the packing nut 568 engages one of the plungerpackings 566. Such engagement compresses the plunger packing 566,creating a tight seal. After a packing nut 568 has been installed withina retainer 544, a central passage within that packing nut 568 will bealigned with a central passage in a plunger packing 566.

Once a sleeve 506, plunger packing 566, retainer 544, and packing nut568 are installed within a pair of aligned horizontal bores 508 and 518,a plunger 574 is next installed, as shown in FIG. 55. Alternatively, theplunger 574 may be installed prior to installing the packing nut 568.Once installed, the plunger 574 is surrounded by the other componentswithin the aligned bores 508 and 518. During operation, the plunger 574moves relative to the fluid end 500 and the components installed withinthe aligned bores 508 and 518.

The plunger 574 is identical to the plunger 296 shown in FIG. 18. Aclamp 576 is attached to the end of each plunger 574. The clamp 576secures its plunger 574 to one of the pony rods 44, show in FIGS. 7 and8.

Turning to FIGS. 65-69, another embodiment of a fluid end 600 is shown.As discussed above, some fluid ends operate with power ends havinglonger-than-usual stay rods. These stay rods extend through the entirefluid end body, rather than through just a machined flange. The fluidend 600 is constructed for use with such power ends.

The fluid end 600 comprises a fluid end body 602 releasably attached toa connect plate 604. A plurality of horizontal bores 606 are formedaround the periphery of the fluid end body 602, as shown in FIGS. 68 and69. The bores 606 interconnect the fluid end body's front and rearsurfaces 608 and 610. Each bore 606 includes a counterbore 612 thatopens on the front surface 608, as shown in FIG. 71.

A plurality of horizontal bores 614 are formed around the periphery ofthe connect plate 604, as shown in FIGS. 68 and 69. The bores 614interconnect the plate's front and rear surfaces 616 and 618. The bores614 and the bores 606 are aligned in a one-to-one relationship, as shownin FIG. 71. Each pair of aligned bores 614 and 606 receives acorresponding one of the stay rods (not shown) of the power end.

When the stay rods are installed in the fluid end 600, a threaded end ofa stay rod projects into each counterbore 612. A nut and washer areinstalled on the projecting end of each stay rod. The nut is turneduntil it presses against a base 620 of the counterbore 612, shown inFIG. 71, thereby securing the fluid end 600 to that stay rod. Like thestay rods 42 shown in FIG. 12, each stay rod may include a step. Thestep of an installed stay rod engages the rear surface 618 of theconnect plate 604.

With reference FIGS. 69 and 70, a plurality of internally threadedopenings 622 are formed about the periphery of the rear surface 610 ofthe fluid end body 602. The openings 622 are registerable with aplurality of passages 624 formed about the periphery of the connectplate 604. Each of the passages 624 includes a counterbore 626 thatopens on the rear surface 618 of the connect plate 604, as shown in FIG.70.

The connect plate 604 is secured to the fluid end body 602 using afastening system 628 shown in FIGS. 68 and 70. The fastening system 628comprises a plurality of threaded screws 630, which are preferablysocket-headed cap screws. Each screw 630 extends through a correspondingpassage 624 in the connector plate 604 and into a corresponding opening622 in the fluid end body 602, as shown in FIG. 70. Each screw 630 isturned until it tightly engages the base 631 of its respectivecounterbore 626, thereby securing the connect plate 604 to the fluid endbody 602.

Continuing with FIG. 70, a plurality of longitudinally spaced horizontalbores 632 are formed in the fluid end body 602. Each bore 632interconnects the front and rear surface 608 and 610 of the fluid endbody 602. In contrast to the fluid end body 102, the fluid end body 602features horizontal bores with unbeveled corners at the rear surface610. More specifically, the walls surrounding the horizontal bores 632form a roughly 90 degree angle with the rear surface.

In contrast to the fluid end body 502, the fluid end body 602 featuresbores 632 that lack any counterbore corresponding to the counterbore 510shown in FIG. 60. A plurality of internally threaded openings 666 areformed in the rear surface 610 of the fluid end body 602. The openings666 surround the openings of the bores 632, as shown in FIG. 69.

Continuing with FIGS. 68 and 69, a plurality of longitudinally spacedhorizontal bores 668 are formed in the connect plate 604. Each bore 668interconnects the front and rear surfaces 616 and 618 of the connectplate 604. The bores 668 and the horizontal bores 632 are aligned in aone-to-one relationship. However, each of the bores 668 has a greaterdiameter than that of each of the bores 632. When the connect plate 604is installed on the fluid end body 602, the peripheral openings 666formed in the fluid end body 602 are exposed to the bores 668 formed inthe connect plate 604, as shown in FIG. 70.

As shown by a comparison of the fluid end 600 shown in FIG. 70 with thefluid end 500 shown in FIG. 60, the fluid end body 602 and connect plate604 are respectively thinner than the fluid end body 502 and connectplate 504. The fluid end 600 uses a thinner fluid end body 602 andconnect plate 604 so that the stay rods have a lesser distance totraverse. The height of the connect plate 604 is reduced relative to theheight of the fluid end body 602, thereby eliminating unnecessarymaterial.

Continuing with FIG. 70, a removable stuffing box sleeve 670 isinstalled within each pair of aligned bores 632 and 668. The sleeve 670includes a lower portion 672 joined directly to a bottom surface 674 ofan upper portion 676. A central passage 678 interconnects the top andbottom surfaces 680 and 682 of the sleeve 670.

A plurality of longitudinal passages 684 are formed in the sleeve 670.Each passage 684 interconnects the top and bottom surfaces 680 and 674of the sleeve's upper portion 676. The longitudinal passages 684 extendparallel to, and are arranged peripherally about, the central passage678. The sleeve 670 is generally identical to the sleeve 506 shown inFIG. 60, except that no annular recesses are formed in its outer surfaceadjacent its top surface 680. The sleeve 670 may have a longer and widerupper portion 676 than that of the sleeve 506.

A plurality of spaced passages 683, preferably two in number, are formedin the sleeve 670, as shown in FIG. 66. The passages 683 are preferablyformed near the midway position along the length of the upper portion676. Each passage 683 interconnects the central passage 678 of thesleeve 670 with its outer surface.

An annular recess 634 is formed in the walls surrounding the horizontalbore 632. The recess 634 receives an annular seal 687. When the sleeve670 is installed, the lower portion 672 is situated within the bore 632,where it is surrounded and engaged by the seal 687. The seal 687 andrecess 634 are identical to the seal 558 and recess 556 shown in FIG.59.

When the sleeve 670 is installed, the bottom surface 674 of its upperportion 676 engages the rear surface 610 of the fluid end body 602. Theupper portion 676 projects from the connect plate 604, with the passages683 positioned outside the rear surface 618. Peripheral passages 684 inthe sleeve 670 and peripheral openings 666 in the body 602 are alignedin a one-to-one relationship. Fluid leaking around an installed plunger689 may exit the sleeve 670 through the passages 683.

The sleeve 670 is secured within the aligned bores 632 and 668 by aretainer 686. Each retainer 686 has a cylindrical body having a centralpassage 688 that interconnects the retainer's top and bottom surfaces690 and 692. A plurality of peripheral passages 694 surround and extendparallel to, the central passage 688. The passages 694, which do notinclude any counterbore, interconnect the top and bottom surfaces 690and 692 of the retainer 686. The passages 694 and the passages 684formed in the sleeve 670 are alignable in a one-to-one relationship.

Continuing with FIG. 70, each of the retainers 686 is secured to thefluid end body 602 using a fastening system 696 shown in FIGS. 68 and69. The fastening system 696 comprises a plurality of studs 698 and aplurality of nuts 700. Each of the studs 698 is received within acorresponding one of the openings 666 formed in the fluid end body 602.From the body 602, each stud 698 extends through a corresponding one ofthe passages 684 in the sleeve 670, and through a corresponding one ofthe passages 694 in the retainer 686.

A first end 702 of each stud 698 projects from the retainer's topsurface 690. A nut 700 is then placed on the first end 702 of each stud698, and turned until it tightly engages the top surface 690 of theretainer 686. In alternative embodiments, the fastening system maycomprise a plurality of screws instead of studs and nuts. The screws arepreferably socket-headed cap screws.

Because each of the retainers 686 is attached to the fluid end body 602using the fastening system 696, no external threads are formed on theouter surface of each of the retainer 686. Likewise, no internal threadsare formed within the walls of each set of aligned bores 632 and 668.

Continuing with FIG. 70, a plunger packing 704 is installed within thecentral passage 678 of each sleeve 670. When installed, the plungerpacking 704 engages an internal seat 705 formed in the sleeve 670. Theplunger packing 704 is identical to the plunger packing 368, shown inFIG. 21.

The plunger packing 704 is held within the sleeve 670 by a packing nut706. The packing nut 706 is generally identical to the packing nut 374shown in FIGS. 46 and 47. However, the packing nut 706 may vary slightlyin size from the packing nut 374 in order to properly fit within theretainer 686 and sleeve 670. External threads formed on the outersurface of the packing nut 706 matingly engage the internal threadsformed in the retainer 686.

When a packing nut 706 is installed within one of the retainers 686, abottom surface 708 of the packing nut 706 engages one of the plungerpackings 704. Such engagement compresses the plunger packing 704,creating a tight seal. After a packing nut 706 has been installed withina retainer 686, a central passage within that packing nut 706 will bealigned with a central passage in a plunger packing 704.

Once a sleeve 670, plunger packing 704, retainer 686, and packing nut706 are installed within a pair of aligned horizontal bores 632 and 668,a plunger 689 is next installed, as shown in FIG. 66. Alternatively, theplunger 689 may be installed prior to installing the packing nut 706.Once installed, the plunger 689 is surrounded by the other componentswithin the aligned bores 632 and 668. During operation, the plunger 689moves relative to the fluid end 600. More particularly, the plunger 689moves relative to those components installed within the aligned bores632 and 668 and the sleeve 670. The plunger 689 is identical to theplunger 296 shown in FIG. 18. A clamp 710 is attached to the end of eachplunger 689. The clamp 710 secures its plunger 689 to one of the ponyrods used with the power end.

With reference to FIGS. 72-74, an alternative embodiment of a dischargeplug 800 is shown. The discharge plug 800 may be used in any of thefluid ends 100, 500, and 600. The discharge plug 800 may replace one ofthe discharge plugs 182 installed within the fluid end 100, 500, or 600.As described below, the discharge plug 800 is configured to form aninterface with a pressure transducer (not shown). The pressuretransducer may be used to measure the magnitude of fluid pressure withinan operating fluid end.

The discharge plug 800 comprises a cylindrical body having opposed topand bottom surfaces 802 and 804. The surfaces 802 and 804 areinterconnected by a central bore 806. Apart from its internal bores, thedischarge plug 800 is of generally solid construction. The bore 806 isthreaded adjacent the bottom surface 804 so that it may receive thepreviously-discussed valve retainer 450. The bore 806 includes acounterbore 808 that opens on the plug's top surface 802.

The plug 800 has the same external shape as the discharge plug 182described with reference to FIGS. 32-34. It includes an upper portion810, a lower portion 812, a tapered portion 814 and a connection portion816. The lower portion 812 has a bottom surface 818. A plurality ofsatellite bores 820 interconnect the central bore 806 with the bottomsurface 818 of the lower portion 812. The satellite bores 820 arerectilinear, and surround the central bore 806, preferably at a uniformangular spacing. The longitudinal axis of the central bore 806 and thelongitudinal axis of each satellite bore 820 define an acute angle inthe direction of the bottom surface 804. None of the satellite bores 820traverses the connection portion 816.

The plug 800 is installed within a fluid end in the same manner as theplug 182 described with reference to FIGS. 32-34. The plug 800 is shownin FIG. 70, installed within a vertical bore 822 formed in the fluid endbody 602. The plug 800 is held in place by the retainer 254 describedwith reference to FIG. 36. However, in place of a retainer nut 262, theretainer is equipped with a gauge port 826, shown in FIGS. 76 and 77.

The gauge port 826 has an elongate body 828 having opposed top andbottom surfaces 830 and 832. External threads are formed in the outersurface of the body 828 adjacent its top and bottom surfaces 830 and832. The external threads adjacent its bottom surface 832 are matinglyengageable with the internal threads formed in the retainer 254. Acentral passage 834 penetrates the body 828 and interconnects the topand bottom surface 830 and 832.

A plurality of openings 833 are formed around the periphery of the body828, near the longitudinal midpoint of the body 828. The openings 833 donot communicate with the central passage 834. The openings 833 allow useof a tool for gripping the body 828 while the gauge port 826 is beinginstalled or removed.

Turning back to FIG. 70, when the gauge port 826 is installed within theretainer 254, its bottom surface 832 engages a top surface 802 of thedischarge plug 800. When engaged, the central passage 834 aligns withthe bore 806 formed in the plug 800. To prevent leakage of fluid, a seal836 may be positioned at the junction of the passage 834 and the bore806. Fluid pressure within the body 602 is transferred, by way ofcentral bore 806 and central passage 834, to the gauge port 826.

The top surface 830 of the gauge port 826 may be placed in engagementwith a pressure transducer. The pressure transducer measures pressure offluid within the central passage 834 of the gauge port 826, which equalspressure within the discharge portion of the fluid end 600. The pressuretransducer may be attached to the gauge port 826 using a hammer union.

With reference now to FIGS. 78 and 79, the fluid end 100 is shown with asafety system 900 installed on the front and top surfaces 176 and 172 ofthe fluid end body 102. If a failure occurs, high fluid pressure maypropel installed or attached components away from the fluid end 100 athigh speeds. The safety system goo tethers the retainer 254, retainernut 262, plug 180 or 182 and fastening system 268 to the fluid end body102. Should a failure occur, the safety system 900 helps to preventthese components from becoming potentially airborne projectiles. Thesafety system goo may also be used with the fluid end 500 or 600.

The safety system 900 comprises a plurality of eyebolts 902 and a cable904. The eyebolts 902 each comprise a threaded end 906 and an opposedlooped end 908, as shown in FIG. 79. The threaded end 906 of eacheyebolt 902 is installed in the threaded hole 190 of each suction plug180, and within the threaded hole 220 of each discharge plug 182. Thethreaded holes 190 and 220 are reached by way of the central opening 290formed in each retainer nut 262. When installed, the looped ends 908 ofthe eyebolts 902 project above the top surface 282 of the retainer nuts262.

A cable 904 is threaded through the looped ends 908 of the eyebolts 902.The cable 904 is preferably made of a strong and tough material, such ashigh-strength nylon or steel. The cable 904 may also be threaded througheyebolts 910 attached to the side surface of the fluid end 100, as shownin FIG. 78. The ends of the cable 904 may be secured together, as shownin the Figures, or each end may be secured to an eyebolt attached to theside surface of the fluid end 100.

Several kits are useful for assembling the fluid end 100, 500, or 600. Afirst kit comprises one of the fluid end bodies and connect platesdescribed herein. The first kit may also comprise one of the fasteningsystems described herein for securing one of the fluid end bodies to oneof the connect plates. Finally, the first kit may further comprise oneof the discharge plugs, suction plugs, seals, retainers, retainer nuts,gauge port, fastening systems, removable stuffing box sleeves, plungerpackings, packing nuts, plungers, clamps, safety system and/or any othercomponents described herein.

The concept of a “kit” is described herein due to the fact that fluidends are often shipped or provided unassembled by a manufacturer, withthe expectation that an end customer will use components of the kit toassemble a functional fluid end. Accordingly, certain embodiments withinthe present disclosure are described as “kits,” which are unassembledcollections of components. The present disclosure also describes andclaims assembled apparatuses and systems by way of reference tospecified kits, along with a description of how the various kitcomponents are actually coupled to one another to form the apparatus orsystem.

The various features and alternative details of construction of theapparatuses described herein for the practice of the present technologywill readily occur to the skilled artisan in view of the foregoingdiscussion, and it is to be understood that even though numerouscharacteristics and advantages of various embodiments of the presenttechnology have been set forth in the foregoing description, togetherwith details of the structure and function of various embodiments of thetechnology, this detailed description is illustrative only, and changesmay be made in detail, especially in matters of structure andarrangements of parts within the principles of the present technology tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed. Changes may be made in theconstruction, operation and arrangement of the various parts, elements,steps and procedures described herein without departing from the spiritand scope of the invention as described in the following claims.

APPENDIX Appendix Introduction

The various fluid end assemblies discussed herein in connection to FIGS.1-79 may include various features discussed in Appendices A-J below.Each of these Appendices discuss different features that may be usedalone or in combination in various embodiments of field ends. Forexample, in various embodiments, a fluid end includes one or morebolt-on retainers (discussed in connection to Appendix A), one or moretapered valve seats (discussed in connection to Appendix B), one or morevalve seats having carbide inserts (discussed in connection to AppendixD and E), seals and sealing surfaces (discussed in connection toAppendix G), one or more plug configured to provide bore clearance(discussed in connection to Appendix I), and that has two-piececonstruction (discussed in connection to Appendix J).

Appendix A: Fluid End with Bolt-on Retainers

Fluid end assemblies are typically used in oil and gas operations todeliver highly pressurized corrosive and/or abrasive fluids to pipingleading to the wellbore. The assemblies are typically attached to powerends run by engines. The power ends reciprocate plungers within theassemblies to pump fluid throughout the fluid end. Fluid may be pumpedthrough the fluid end at pressures that range from 5,000-15,000 poundsper square inch (psi). Fluid used in high pressure hydraulic fracturingoperations is typically pumped through the fluid end at a minimum of8,000 psi; however, fluid will normally be pumped through the fluid endat pressures around 10,000-15,000 psi during such operations.

In fluid end assemblies known in the art, the fluid flow passages orbores formed within the fluid end body are typically sealed by insertinga plug into each bore. A large retaining nut is then installed into eachbore above the plug. The retaining nuts typically thread into internalthreads formed in the walls of each bore.

In operation, the high level of fluid pressure pumping throughout thefluid end may cause the retaining nuts to back off or unthread fromtheir installed position. When a retaining nut unthreads from itsinstalled position, the plug it was retaining may be displaced by fluidpressure. Displacement of the plug allows fluid to leak around the plugand erode the walls of the bore. The internal threads formed in thebores for engagement with the retaining nuts are also known to crackover time. Erosion of the bore walls or cracking of the internal threadstypically requires repair or replacement of the fluid end.

A plurality of different fluid ends have bores sealed without threadingretaining nuts into the walls of each bore. As a result, the fluid endsdo not have internal threads formed in their bores proximate the boreopenings. Removal of the internal threads eliminates the problemsassociated with the internal thread failures and the retaining nutsbecoming unthreaded from the bores.

With reference to FIGS. 80 and 82, a fluid end 100 is shown. The fluidend Moo comprises a fluid end body A102 having a flat external surfaceA104 and a plurality of first and second bores A106, A108 formedadjacent one another therein, as shown in FIG. 80. The number of firstbores 106 equals the number of second bores A108. Each first bore 106intersects its paired second bore A108 within the fluid end body A102 toform an internal chamber A112, as shown in FIG. 82.

FIG. 80 shows five first and second bores A106, A108. In alternativeembodiments, the number of sets of paired first and second bores in thefluid end body may be greater than five, or less than five. Thus, FIG.83 shows a fluid end body that includes three sets of paired first andsecond bores. Each bore of each set of paired bores A106 and A108terminates in a corresponding opening A110 formed in the externalsurface A104. The bores A106 and A108 and openings A110 exist inone-to-one relationship. A plurality of internally threaded openingsA144 are formed in the body A102 and uniformly spaced around each boreopening A110, as shown in FIG. 80.

With reference to FIG. 82, each second bore A108 may have an intakeopening A118 formed proximate the bottom end of the fluid end body A102.Each intake opening A118 is connected in one-to-one relationship to acorresponding coupler or pipe. These couplers or pipes are fed from asingle common piping system (not shown). A pair of valves A120 and A122are positioned within each second bore A108. The valves A120, A122 routefluid flow within the body A102. The intake valve A120 blocks fluidbackflow through the intake opening A118. The discharge valve A122regulates fluid through one or more discharge openings A126. A pluralityof couplers A127 may be attached to each discharge opening A126 forconnection to a piping system (not shown), as shown in FIG. 80.

With reference again to FIGS. 80-94, and the reference characters usedthere in, each of the components A128 and A130 comprises a first sectionA138 joined to a second section A140. The first section A138 has afootprint sized to cover the bore opening A110 and the second sectionA140 is configured for removable receipt within one of the bores A106,A108. In one embodiment, the first section A138 is an enlarged plate andthe second section A140 is a plug sized to be closely received withinone of the bores A106, A108. When the component A128 or A130 isinstalled within one of the bores A106, A108, the first section A138engages with the external surface A104 of the body A102. This engagementprevents longitudinal movement of the second section A140 within thebore A106 or A108 as shown in FIG. 82.

With reference to FIG. 80, the first section A138 may be formed as acircular structure having a plurality of notches A142 cut from its outerperiphery. When each of the first sections A138 is engaged with theexternal surface A104 of the body A102, each of the notches A142partially surrounds one of the openings A144 spaced around each boreopening A110.

Continuing with FIGS. 80 and 82, once each component A128, A130 isinstalled in the fluid end body A102, each of the components A128, A130is secured in place by a retainer element A132 in a one-to-onerelationship. Each retainer element A132 has a footprint sized to fullycover the first section A138 of the components A128 and A130. Theretainer elements A132 shown in FIG. 80 are flat and cylindrical. Aplurality of openings A146 are formed about the periphery of eachretainer element A132. Each opening A146 is alignable with acorresponding one of the openings A144 in a one-to-one relationship.

Each of the retainer elements A132 is secured to the fluid end body A102using a fastening system A134. The fastening system comprises aplurality of studs A148, a plurality of washers A150, and a plurality ofnuts A152. Each stud A148 is externally threaded adjacent its first endA149, while each opening A144 has internal threads that mate with thoseof the stud A148. Each stud A148 may be threaded into place within acorresponding one of the openings A144, in a one-to-one relationship.

Once a first stud A148 has been installed in the body A102 at its firstend A149, its opposed second end A151 projects from the body's externalsurface A104. When each component A128 is positioned within its boreA106, each of its notches A142 at least partially surrounds acorresponding one of the studs A148. Likewise, when each component A130is positioned within its bore A108, each of its notches A142 at leastpartially surrounds a corresponding one of the studs A148.

Each peripheral opening A146 formed in each of the retainer elementsA132 is registerable with a corresponding one of the studs A148. Theplurality of washers A150 and nuts A152 may be installed and torqued oneach one of the studs A148. The plurality of washers A150 and nuts A152hold the retainer element A132 against the first section A138 of thecomponents A128, A130 and hold the first section A138 against theexternal surface A104 of the fluid end body A102. Because each of theretainer elements A132 is attached to the fluid end body A102 using thefastening system A134, no external threads are formed on the outersurface of each retainer element A132. Likewise, no internal threads areformed within the walls of each bore A106, A108.

With reference to FIGS. 81 and 82, a plunger end A154 of the fluid endA100 is shown. The plurality of first bores A106 terminate at openingsA156 formed on the external surface A104 of the plunger end A154. Aninternal seat A159 is formed in the walls of each of the bores A106proximate each of the bore openings A156. A plurality of threadedopenings A161 are formed in each of the internal seats A159, as shown inFIG. 81.

A component A158 is positioned within each first bore A106 through eachof the openings A156. Each of the components A158 is tubular and sizedto be closely received within each bore A106. In one embodiment, thecomponents A158 are stuffing box sleeves.

With reference to FIG. 82, each of the components A158 may have a firstsection A160 that joins a second section A162 via a tapered sectionA164. The first section A160 may have a larger diameter than the secondsection A162. When each of the components A158 are installed within eachof the bores A106, the tapered section A164 engages a tapered seat A166formed in the walls of each bores A106. This engagement preventslongitudinal movement of each component A158 within each bore A106. Aseal A167 is positioned around the outer surface of the second sectionA162 of each of the components A158 in order to block fluid from leakingfrom the bores A106.

Once installed within the body A102, each component A158 is secured inplace by a retainer element A170 in a one-to-one relationship. Each ofthe retainer elements A170 is sized to be closely received within eachbore A106 and engage a top surface A171 of each component A158, as shownin FIG. 82. Each of the retainer elements A170 shown in FIG. 81 has acylindrical body and a threaded central opening A172. A plurality ofopenings A174 are formed about the periphery of each of the retainerelements A170. The openings A174 are uniformly spaced around eachcentral opening A172.

A plurality of ports A175 may be formed in an outer surface of eachretainer element A170 that are orthogonal to the plurality of openingsA174. At least one seal A176 may also be disposed around the outersurface of each of the retainer elements A170. The seal A176 helps blockfluid from leaking from the bores A106.

Each of the retainer elements A170 is secured to the fluid end body A102using a fastening system A178. The fastening system A178 comprises aplurality of threaded screws A180. The screws A180 may be socket-headedcap screws.

The fastening system A178 secures each retainer element A170 to eachinternal seat A159. When each retainer element A170 is positioned withineach bore A106, each of the peripheral openings A174 is alignable with acorresponding one of the openings A161 in a one-to-one relationship.Each of the screws A180 is registerable within one of the openings A161in the seat A159 and one of the peripheral openings A174 in the retainerelement A170.

The screws A180 may be torqued as desired to tightly attach each of theretainer elements A170 to each internal seat A159 and securely hold eachcomponent A158 within each bore A106. Because each of the retainerelements A170 is attached to the fluid end body A102 using the fasteningsystem A178, no external threads are formed on the outer surface of eachof the retainer elements A170. Likewise, no internal threads are formedwithin the walls of each bore A106 on the plunger end A154 of the bodyA102.

Continuing with FIGS. 81-82, a plurality of packing seals A181 may bepositioned within each of the components A158 and each of the retainerelements A170 to prevent fluid from leaking from the bores A106. Atleast one of the packing seals A181 may have a plurality of ports A179formed in its outer periphery, as shown in FIG. 81. The ports A179provide an exit for fluid trapped within the packing seals A181. Fluidexiting the ports A179 may exit the retainer element A170 through theports A175.

A packing nut A182 may also be threaded into the central opening A172 ofeach of the retainer elements A170 in a one-to-one relationship. Thepacking nut A182 has a threaded section A183 joined to a body A184. Thebody A184 shown in FIG. 81 is cylindrical. However, the body A184 mayalso be square or rectangular shaped. A central passage A185 extendsthrough the threaded section A183 and the body A184. The threadedsection A183 of the packing nut A182 is threaded into the centralopening A172 of the retainer element A170.

When installed within each of the retainer elements A170, each of thepacking nuts A182 engages with and compresses the packing seals A181installed within each component A158 and retainer element A170, as shownin FIG. 82. Compression of the packing seals A181 helps prevent fluidfrom leaking past the seals A181. A seal A186 may also be positionedwithin the central passage A185 of each of the packing nuts A182 tofurther seal fluid from leaking from the bores A106.

A plurality of holes A187 are formed around the outer surface of each ofthe packing nut bodies A184. The holes A187 serve as connection pointsfor a spanner wrench that may be used to tightly thread the packing nutA182 into the central opening A172 of each of the retainer elementsA170.

A plunger A188 may also be installed within each bore A106 in aone-to-one relationship. When a plunger A188 is installed within a boreA106, the plunger A188 is positioned within the component A158, theretainer element A170, and the packing nut A182, as shown in FIG. 82.Each of the plungers A188 projects from the plunger end A154 of thefluid end body A102 and is attached to a separate power end. Asdiscussed above, the power end reciprocates each of the plungers A188within the fluid end body A102 so as to pump fluid throughout the body.Each of the plungers A188 may be attached to the power end via a clampA190 in a one-to-one relationship.

Several kits are useful for assembling the fluid end A100. A first kitcomprises a plurality of the components A128 or A130, a plurality of theretainer elements A132, and the fastening system A134. A second kit maycomprise the plurality of components A158, a plurality of the retainerelements A170, and the fastening system A178. The second kit may furthercomprise a plurality of the packing seals A181, a plurality of thepacking nuts A182, and a plurality of the plungers A188. Each of thekits may be assembled using the fluid end body A102.

With reference to FIGS. 83 and 85, a second embodiment of a fluid endA200 is shown. The fluid end A200 comprises a fluid end body A202 havinga flat external surface A204 and a plurality of first and second boresA206, A208 formed adjacent one another therein, as shown in FIG. 83.Each bore of each set of paired bores A206 and A208 terminates in acorresponding opening A210 formed in the external surface A204. Aplurality of threaded openings A211 are formed in the body A202 anduniformly spaced around each opening A210. The internal functions of thefluid end A200 are identical to those described with reference to fluidend Moo, shown in FIG. 82.

The fluid end A200 further comprises a plurality of sets of componentsA212 and A214. The number of sets may equal the number of set of pairedfirst and second bores A206 and A208 formed in the body A202. Thecomponent A212 is positioned within a first bore A206, and the componentA214 is positioned within its paired second bore A208. In oneembodiment, the component A212 is a suction plug and the component A214is a discharge plug.

Each of the components A212 and A214 is substantially identical in shapeand construction, and is sized to fully block fluid flow within therespective bore A206, A208. A seal A216 is positioned around the outersurface of each component A212, A214 to block fluid from leaking fromthe bores A206, A208.

As shown in FIG. 83, a top surface A213 of each component A212, A214 maysit flush with the external surface A204 of the body A202 when installedwithin a respective bore A206, A208. Each of the components A212 andA214 may engage with internal seats (not shown) formed in the walls ofeach of the bores A206, A208. Such engagement helps prevent longitudinalmovement of the components A212, A214 within the respective bore A206,A208.

Once installed within the fluid end body A202, each component A212 andA214 is secured in place by a retainer element A218 in a one-to-onerelationship. Each of the retainer elements A218 has a footprint sizedto cover a single bore opening A210. The retainer elements A218 shown inFIG. 83 are flat and cylindrical. A plurality of openings A220 areformed about the periphery of each retainer element A218. Eachperipheral opening A220 is alignable with a corresponding one of theopenings A211 in a one-to-one relationship, as shown in FIG. 83.

The retainer elements A218 are secured to the external surface A204 ofthe fluid end body A202 by a fastening system A222. The fastening systemA222 comprises a plurality of externally threaded studs A224, aplurality of washers A226, and a plurality of internally threaded nutsA228. Each stud A224 is externally threaded adjacent its first end A230,while each opening A211 has internal threads that mate with those of thestud A224. Each stud A224 may be threaded into place within acorresponding one of the openings A211, in a one-to-one relationship.

Once a first stud A224 has been installed in the body A202 at its firstend A230, its opposed second end A232 projects from the body's externalsurface A204. Each peripheral opening A220 formed in the retainerelements A218 is registerable with a corresponding one of the studsA224. The plurality of washers A226 and nuts A228 may be installed andtorqued on each of the studs A224. The plurality of washers A226 andnuts A228 hold the retainer elements A218 against the external surfaceA204 of the fluid end body A202. Because each of the retainer elementsA218 is attached to the fluid end body A202 using the fastening systemA222, no external threads are formed on the outer surface of eachretainer element A218. Likewise, no internal threads are formed withinthe walls of each bore A206 and A208.

With reference to FIGS. 84-85, a plunger end A234 of the fluid end A200is shown. The plurality of first bores A206 terminate at openings A236formed on the external surface A204 of the plunger end A234. The plungerend A234 of the fluid end body A202 is similar to the plunger end A154of fluid end body A102, shown in FIGS. 81-82, except that an internalseat A159 is not formed within each bore A206. Instead, a plurality ofinternally threaded openings A238 are formed in the external surfaceA204 of the fluid end body A202 that are uniformly spaced around eachbore opening A236.

A component A240 is positioned within each first bore A206 through eachof the openings A236 in a one-to-one relationship. Each of thecomponents A240 is tubular and sized to be closely received within eachbore A206. In one embodiment, the components A240 are stuffing boxsleeves.

With reference to FIG. 85, each of the components A240 may have a firstsection A242 that joins a second section A244 via a tapered sectionA246. The first section A242 may have a larger diameter than the secondsection A244. When each of the components A240 are installed within eachof the bores A206, the tapered section A246 engages a tapered seat A248formed in the walls of each bore A206. This engagement preventslongitudinal movement of each component A240 within each bore A206. Aseal A250 is positioned around the outer surface of the second sectionA244 of each of the components A240 to block fluid from leaking from thebores A206.

Once installed within the body A202, a top surface A252 of each of thecomponents A240 may sit flush with the external surface A204 of the bodyA202. Each of the components A240 is secured in place within each boreA206 by a retainer element A254 in a one-to-one relationship. Theretainer elements A254 shown in FIG. 84 have a cylindrical body and athreaded central opening A256. A plurality of openings A258 are formedabout the periphery of each of the retainer elements A254. The openingsA258 are uniformly spaced around each central opening A256.

The retainer elements A254 are secured to the external surface A204 ofthe fluid end body A202 using a fastening system A260. The fasteningsystem A260 comprises a plurality of threaded screws A262. The screwsA262 may be socket-headed cap screws. When each retainer element A254 ispositioned over each bore opening A236, each of the peripheral openingsA258 is alignable with a corresponding one of the openings A238 in aone-to-one relationship. Each of the screws A262 is registerable withinone of the openings A238 in the body A202 and one of the peripheralopenings A258 in each of the retainer elements A254.

The screws A262 may be torqued as desired to tightly attach each of theretainer elements A254 to the body A202 and securely hold each of thecomponents A240 within each bore A206. Because each of the retainerelements A254 is attached to the fluid end body A202 using the fasteningsystem A260, no external threads are formed on the outer surface of eachretainer element A254. Likewise, no internal threads are formed withinthe walls of each bore A206 on the plunger end A234 of the body A202.

Similar to the plunger end A154 shown in FIG. 81, a plurality of packingseals A264 may be positioned within each of the components A240. Apacking nut A266 may thread into the central opening A256 of eachretainer element A254 and compress the packing seals A264. A seal A267may also be positioned within each packing nut A266. Additionally, aplurality of plungers A268 may be disposed within each component A240,retainer element A254, and packing nut A266. Each of the plungers A268may be attached to a power end via a clamp A270.

In alternative embodiments, the components A212, A214, and A240 may notbe flush with the external surface A204 of the body A202 when installedin the respective bores A206, A208. In such case, a flange or ledge maybe formed on each of the retainer elements A218 or A254 on its sidefacing the component A212, A214, or A240. The flange or ledge may beinstalled within the bores A206, A208 so that it tightly engages the topsurface A213 or A252 of the components A212, A214, or A240.

Likewise, if the components A212, A214, or A240 project from theexternal surface A204 of the body A202 when installed within therespective bores A206, A208, the retainer elements A218 or A254 can bemodified to accommodate the component A212, A214, or A240. For example,a cut-out may be formed in the retainer element A218 or A254 for closelyreceiving the portion of the component A212, A214, or A240 projectingfrom the body A202. The area of the retainer element A218 or A254surrounding the cut-out will engage the external surface A204 of thebody A202.

Several kits are useful for assembling the fluid end A200. A first kitcomprises a plurality of the components A212 or A214, a plurality ofretainer elements A218, and the fastening system A222. A second kit maycomprise the plurality of components A240, a plurality of the retainerelements A254, and the fastening system A260. The second kit may furthercomprise a plurality of packing seals A264, a plurality of packing nutsA266, and a plurality of plungers A268. Each of the kits may beassembled using the fluid end body A202.

Turning now to FIG. 86, a third embodiment of a fluid end A300 is shown.The fluid end A300 comprises a fluid end body A302 having a flatexternal surface A304 and a plurality of first and second bores A306,A308 formed adjacent one another therein. Each bore of each set ofpaired bores A306 and A308 terminates in a corresponding opening A310formed in the external surface A304. A plurality of threaded openingsA311 are formed in the body A302 and uniformly spaced around each boreopening A310. The internal functions of the fluid end A300 are identicalto those described with reference to fluid end A100, shown in FIG. 82.

The fluid end A300 further comprises a plurality of sets of componentsA312 and A314. The number of sets, in some embodiments, equals thenumber of sets of paired first and second bores A306 and A308 formed inthe body A302. The component A312 is positioned within a first boreA306, and the component A314 is positioned within its paired second boreA308. In one embodiment, the component A312 is a suction plug and thecomponent A314 is a discharge plug. A seal A315 is positioned aroundeach of the components A312, A314 to block fluid from leaking from therespective bores A306, A308.

The components A312 and A314 have the same shape and construction as thecomponents A212 and A214 shown in FIGS. 83 and 85. Each of thecomponents A312 and A314 may engage with internal seats (not shown)formed in the walls of each of the bores A306, A308. Such engagementhelps prevent longitudinal movement of the components A312, A314 withinthe respective bores A306, A308.

Once installed within the body A302, a top surface A313 of each of thecomponents A312, A314 may sit flush with the external surface A304 ofthe body A302. Each of the components A312, A314 is secured within eachrespective bore A306, A308 by a retainer element A316. Each of theretainer elements A316 shown in FIG. 86 is a large rectangular platehaving a footprint sized to cover a plurality of adjacent bore openingsA310 at one time. A plurality of openings A318 are formed in eachretainer element A316 that are alignable with a corresponding one of theopenings A311 in a one-to-one relationship.

Each of the retainer elements A316 is secured to the external surfaceA304 of the fluid end body A302 by a fastening system A320. Thefastening system A320 comprises a plurality of externally threaded studsA322, a plurality of washers A324, and a plurality of internallythreaded nuts A326. The fastening system A320 secures each of theretainer elements A316 on the fluid end body A302 in the same way asdescribed with reference to the fastening system A222 used with thefluid end A200.

Because each of the retainer elements A316 is attached to the fluid endbody A302 using the fastening system A320, no external threads areformed in the retainer element A316. Likewise, no internal threads areformed within the walls of each bore A306 and A308.

When the retainer elements A316 are installed on the fluid end bodyA302, the edges of the retainer element A316 may extend far enough so asto sit flush with the edges of the fluid end body A302. In alternativeembodiments, the retainer element A316 may have different shapes orsizes. For example, the retainer element A316 may be large enough so asto cover an entire side surface of the fluid end body A302.Alternatively, the retainer elements A316 may have rounded edges, asshown in FIG. 87.

Turning to FIG. 87, a plunger end A330 of the fluid end A300 is shown.The plurality of first bores A306 terminate at openings A332 formed onthe external surface A304 of the plunger end A330. A plurality ofinternally threaded openings A334 are formed in the external surfaceA304 that are uniformly spaced around each bore opening A332.

A component A336 is positioned within each first bore A306 through eachof the openings A332. Each of the components A336 is tubular and sizedto be closely received within each bore A306. In one embodiment, thecomponents A336 are stuffing box sleeves. The components A336 have thesame shape and construction as the components A240, shown in FIGS.84-85.

Once installed within the body A302, a top surface A346 of each of thecomponents A336 may sit flush with the external surface A304 of the bodyA302. Each of the components A336 is secured within each bore A306 by asingle retainer element A348. The retainer element A348 shown in FIG. 87is a large oval plate having a footprint sized to cover a plurality ofadjacent bore openings A332 formed on the plunger end A330 of the fluidend body A302. A plurality of openings A350 are formed in the retainerelement A348 that are alignable with a corresponding one of the openingsA334 in a one-to-one relationship.

In alternative embodiments, the retainer element A348 may have differentshapes or sizes. For example, the retainer element A348 may be largeenough so as to cover an entire side surface of the fluid end body A302.Alternatively, the retainer element A348 may have squared edges, asshown in FIG. 86.

The retainer element A348 is secured to the external surface A304 of thefluid end body A302 by a fastening system A352. The fastening systemA352 comprises a plurality of screws A354. The fastening system A352secures the retainer element A348 on the fluid end body A302 in the sameway as described with reference to the fastening system A260 used withthe fluid end A200 and shown in FIGS. 84-85.

Because the retainer element A348 is attached to the fluid end body A302using the fastening system A352, no external threads are formed in theretainer element A348. Likewise, no internal threads are formed withinthe walls of each bore A306.

A central threaded opening A356 is formed in the center of each groupingof openings A350 in the retainer element A348. The openings A356 arealignable with each bore opening A332 in a one-to-one relationship. Asingle packing nut A358 may thread into each central opening A356. Aseal A359 may be positioned within each packing nut A358.

Similar to the plunger end A234 shown in FIGS. 84-85, a plurality ofpacking seals A360 may be positioned within each component A336. Each ofthe packing nuts A358 may compress the packing seals A360 when installedwithin the retainer element A348. A plurality of plungers A362 may bedisposed within each component A336, the retainer element A348, and eachpacking nut A358. Each of the plungers A362 may be connected to a powerend via a clamp A364. A cross-sectional view of the fluid end A300 looksidentical to the cross-sectional view of the fluid end A200, shown inFIG. 85.

Several kits are useful for assembling the fluid end A300. A first kitcomprises a plurality of the components A312 or A314, a retainer elementA316, and the fastening system A320. A second kit may comprise aplurality of the components A336, a retainer element A348, and thefastening system A352. The second kit may further comprise a pluralityof the packing seals A360, a plurality of the packing nuts A358, and aplurality of the plungers A362. Each of the kits may be assembled usingthe fluid end body A302.

With reference to FIGS. 88 and 90, a fourth embodiment of a fluid endA400 is shown. The fluid end A400 comprises a fluid end body A402 havinga flat external surface A404 and a plurality of first and second boresA406, A408 formed adjacent one another therein, as shown in FIG. 88.Each bore of each set of paired bores A406 and A408 terminates in acorresponding opening A410 formed in the external surface A404. Aplurality of threaded openings A411 are formed in the body A402 anduniformly spaced around each opening A410. The internal functions of thefluid end A400 are identical to those described with reference to fluidend Moo, shown in FIG. 82.

The fluid end A400 further comprises a plurality of sets of componentsA412 and A414. The number of sets equals the number of set of pairedfirst and second bores A406 and A408 formed in the body A402. Thecomponent A412 is positioned within a first bore A406, and the componentA414 is positioned within its paired second to bore A408. In oneembodiment, the component A412 is a suction plug and the component A414is a discharge plug. A seal A415 is positioned around the outer surfaceof each of the components A412, A414 to block fluid from leaking fromthe respective bores A406, A408.

The components A412 and A414 have substantially the same shape andconstruction as the components A212 and A214 shown in FIGS. 83 and 85.However, in contrast to the components A212, A214, each of thecomponents A412 and A414 is joined to a single retainer element A416.

The components A412, A414 may be welded or fastened to the center of theback surface of each retainer element A416. Alternatively, each of thecomponents A412 or A414 and a corresponding retainer element A416 may bemachined as a single piece, as shown in FIG. 90. Each of the retainerelements A416 secures each of the components A412, A414 within therespective bores A406, A408. The retainer elements A416 also prevent thecomponents A412, A414 from moving longitudinally within the respectivebores A406, A408.

A plurality of openings A418 are formed about the periphery of eachretainer element A416. Each peripheral opening A418 is alignable with acorresponding one of the openings A411 in a one-to-one relationship, asshown in FIG. 88.

The retainer elements A416 are secured to the external surface A404 ofthe body A402 using a fastening system A420. The fastening system A420comprises a plurality of externally threaded studs A422, a plurality ofwashers A424, and a plurality of internally threaded nuts A426. Thefastening system A420 secures the retainer elements A416 to the fluidend body A402 in the same way as described with reference to thefastening system A222 used with the fluid end A200.

Because the retainer elements A416 are attached to the fluid end bodyA402 using the fastening system A420, no external threads are formed inthe retainer elements A416. Likewise, no internal threads are formedwithin the walls of each bore A406 and A408.

Turning now to FIGS. 89-90, a plunger end A430 of the fluid end A400 isshown. The plurality of first bores A406 terminate at openings A432formed on the external surface A404 of the plunger end A430. A pluralityof internally threaded openings A434 are formed in the external surfaceA404 that are uniformly spaced around each bore opening A432.

A component A436 is positioned within each first bore A406 through eachof the openings A432. Each of the components A436 is tubular and sizedto be closely received within each bore A406. In one embodiment, thecomponents A436 are stuffing box sleeves. The components A436 havesubstantially the same shape and construction as the components A240,shown in FIGS. 84-85. However, in contrast to the components A240, eachof the components A436 is joined to a single retainer element A438.

The components A436 may be welded or fastened to the center of the backsurface of each retainer element A438. Alternatively, each of thecomponents A436 and a corresponding retainer element A438 may bemachined as a single piece, as shown in FIG. 90. Each of the retainerelements A438 secures each of the components A436 within the bores A406.The retainer elements A438 also prevent the components A436 from movinglongitudinally within the bores A406.

A threaded central opening A440 is formed within each retainer elementA438. A plurality of threaded openings A442 are formed about theperiphery of each of the retainer elements A438 and are uniformly spacedaround each central opening A440. Each peripheral opening A442 isalignable with a corresponding one of the openings A434 in a one-to-onerelationship, as shown in FIG. 89.

The retainer elements A438 are secured to the external surface A404 ofthe body A402 using a fastening system A444. The fastening system A444comprises a plurality of screws A446. The fastening system A444 securesthe retainer elements A438 to the fluid end body A402 in the same way asdescribed with reference to the fastening system A260 used with thefluid end A200 and shown in FIGS. 84-85.

Because the retainer elements A438 are attached to the fluid end bodyA402 using the fastening system A444, no external threads are formed inthe retainer elements A416. Likewise, no internal threads are formedwithin the walls of each bore A406 on the plunger end A430 of the bodyA402.

Like the plunger end A330 of fluid end A300, the fluid end A400 may alsocomprise a plurality of packing seals A448, a plurality of packing nutsA450, each housing a seal A454, and a plurality of plungers A456. Eachplunger A456 may be connected to a power end via a clamp A458.

Several kits are useful for assembling the fluid end A400. A first kitcomprises a plurality of the components A412 or A414, a plurality of theretainer elements A416, and the fastening system A420. A second kit maycomprise a plurality of the components A436, a plurality of the retainerelements A438, and the fastening system A444. The second kit may furthercomprise a plurality of the packing seals A448, a plurality of thepacking nuts A450 and a plurality of the plungers A456. Each of the kitsmay be assembled using the fluid end body A402.

With reference to FIGS. 91-92, a fifth embodiment of a fluid end A500 isshown. The fluid end A500 comprises a fluid end body A502 having a flatexternal surface A504 and a plurality of first and second bores A506,A508 formed adjacent one another therein, as shown in FIG. 91. Each boreof each set of paired bores A506 and A508 terminates in a correspondingopening A510 formed in the external surface A504. A plurality ofthreaded openings A511 are formed in the body A502 and uniformly spacedaround each opening A510. The internal functions of the fluid end A500are identical to those described with reference to fluid end A100, shownin FIG. 82.

The fluid end A500 further comprises a plurality of sets of componentsA512 and A514. The number of sets equals the number of set of pairedfirst and second bores A506 and A508 formed in the body A502. Thecomponent A512 is positioned within a first bore A506, and the componentA514 is positioned within its paired second bore A508. In oneembodiment, the component A512 is a suction plug and the component A514is a discharge plug. The components A512 and A514 have the same shapeand construction as the components A212 and A214 shown in FIGS. 83 and85. A seal A516 is positioned around the outer surface of each componentA512, A514 to block fluid from leaking from the bores A506, A508.

As shown in FIG. 91, a top surface A513 of each of the components A512,A514 may sit flush with the external surface A504 of the body A502 wheninstalled within a respective bore A506, A508. Each of the componentsA512 and A514 may engage with internal seats (not shown) formed in thewalls of each of the bores A506, A508. Such engagement helps preventlongitudinal movement of the components A512, A514 within the respectivebore A506, A508.

Once installed within the fluid end body A502, each component A512 andA514 is secured in place by a retainer element A518 in a one-to-onerelationship. Each of the retainer elements A518 has a footprint sizedto cover a single bore opening A510. The retainer elements A518 shown inFIG. 91 are flat and cylindrical and each have a central threadedopening A519. A plurality of openings A520 are formed about theperiphery of each retainer element A518 and are uniformly spaced aroundeach central opening A519. Each peripheral opening A520 is alignablewith a corresponding one of the openings A511 in a one-to-onerelationship, as shown in FIG. 91.

The retainer elements A518 are secured to the external surface A504 ofthe fluid end body A504 by a fastening system A522. The fastening systemA522 comprises a plurality of externally threaded studs A524, aplurality of washers A526, and a plurality of internally threaded nutsA528. The fastening system A522 secures the retainer elements A518 tothe fluid end body A502 in the same way as described with reference tothe fastening system A222 used with the fluid end A200 shown in FIGS. 83and 85.

Each central opening A519 formed in each retainer element A518 isalignable with each corresponding bore opening A510 in a one-to-onerelationship. A retaining nut A530 may thread into each central openingA519 to cover each bore opening A510. Using a threaded retaining nutA530 with the retainer element A518 allows access to each bore openingA510 without having to remove the retainer elements A518 from the fluidend body A502.

While the fluid end A500 uses a threaded retaining nut A530, theretaining nut A530 is not threaded into the walls of the bores A506,A508. Thus, any failures associated with the retaining nut A530 may beexperienced in the retainer element A518, which is easily replaceable.This similar configuration is used on the plunger end A234 of the fluidend A200 shown in FIGS. 84-85. Such configuration is shown again on aplunger end A532 of the fluid end body A502 in FIG. 92.

A kit is useful for assembling the fluid end A500. The kit may comprisea plurality of the components A512 or A514, a plurality of the retainerelements A518, and the fastening system A522. The kit may furthercomprise a plurality of retaining nuts A530. The kit may be assembledusing the fluid end body A502.

Turning now to FIG. 93, a sixth embodiment of a fluid end A600 is shown.The fluid end A600 comprises a fluid end body A602 having a flatexternal surface A604 and a plurality of first bores (not shown) andsecond bores A608 formed adjacent one another therein. Each bore of eachset of paired bores terminates in a corresponding opening A610 formed inthe external surface A604. A plurality of threaded openings A611 areformed in the body A602 and uniformly spaced around each opening A610.The internal functions of the fluid end A600 are identical to thosedescribed with reference to fluid end A100, shown in FIG. 82.

The fluid end A600 further comprises a plurality of sets of componentsA614. The component A614 is positioned within a second bore A608. Thecomponents positioned within each first bore are not shown in FIG. 93.However, such components are identical in shape and construction to thecomponents A614.

The number of sets of components equals the number of set of pairedfirst bores (not shown) and second bores A608 formed in the body A602.In one embodiment, the component positioned within a first bore is asuction plug, and the component A614 is positioned within its pairedsecond bore A608 is a discharge plug. The components A614 have asubstantially similar shape and construction as the components A212 andA214 shown in FIGS. 83 and 85, except that a threaded hole A616 isformed in a top surface A613 of each component A614. A seal A618 ispositioned around the outer surface of each component A614 to blockfluid from leaking from the bores A608.

The top surface A613 of each component A614 may sit flush with theexternal surface A604 of the body A602 when installed within a boreA608. Each of the components A614 may engage with internal seats (notshown) formed in the walls of each of the bores A608. This engagementhelps prevent longitudinal movement of the components A614 within thebore A608. Likewise, the components positioned within the first bores(not shown) may engage internal seats formed within the walls of thefirst bores.

Once installed within the fluid end body A602, each component A614 issecured by a retainer element A620 in a one-to-one relationship.Likewise, the components positioned within the first bores (not shown)are each secured by one of the retainer elements A620. Each of theretainer elements A620 has a footprint sized to cover a single boreopening A610. The retainer elements A620 shown in FIG. 93 are flat andcylindrical and each have a central threaded opening A622. A pluralityof openings A624 are formed about the periphery of each retainer elementA620 and are uniformly spaced around each central opening A622. Eachperipheral opening A624 is alignable with a corresponding one of theopenings A611 in a one-to-one relationship.

The retainer elements A620 are secured to the external surface A604 ofthe fluid end body A602 by a fastening system A626. The fastening systemA626 comprises a plurality of externally threaded studs A628, aplurality of washers (not shown), and a plurality of internally threadednuts A630. The fastening system A626 secures the retainer elements A620to the fluid end body A602 in the same way as described with referenceto the fastening system A222 used with the fluid end A200 shown in FIGS.83 and 85.

The fastening system A626 may further comprise a plurality of eye boltsA632, a plurality of handles A634, and a cable A636. Each eye bolt A632has external threads A638 formed on its first end and an eye A640 formedon its opposite second end. The threaded end A638 of each eye bolt A632threads into each hole A616 formed in each component A614 in aone-to-one relationship. Once installed within each hole A614, the eyeA640 of each eyebolt A632 projects through the central opening A622formed in each retainer element A620.

Each of the handles A634 has a threaded section A642 joined to acylindrical body A644. A central passage A646 extends through thethreaded section A642 and the body A644. Each of the threaded sectionsA642 may be installed within the central opening A622 of each of theretainer elements A620 such that each eye bolt A632 is disposed withinthe central passage A646. Once one of the handles A634 is installed in aretainer element A620, the eye bolt A632 projects from the handle A634.The handle A634 helps support the eye bolt A632 and provides a grip toassist in installation or removal of a retainer element A620 on thefluid end body A602.

The cable A636 may be disposed through each eye A640 of each eye boltA632. Each of the eye bolts A632 may be oriented to facilitate thepassage of the cable A636 through each eye A640. The ends of the cableA636 may be attached to the external surface A604 of the fluid end bodyA602 using eye bolts A650 and clamps A652. The cable A636 may be made ofa stiff and tough material, such as high-strength nylon or steel.

In operation, the eyebolts A632 and cable A636 tether each of theretaining elements A620 and components A614, in case of failure of theretainer elements A620, a portion of the fastening system A626, or thefluid end body A602. When a failure occurs, the large pressure in thefluid end body A602 will tend to force the components A614 out of theirrespective bores A608 with a large amount of energy. The cable A636helps to retain the components A614 within the bores A608 in the eventof a failure. The cable A636 also helps to retain the retainer elementsA620 in position in the event of a failure. The fastening systems A134,A222, A320, A420, and A522 used with fluid ends A100, A200, A300, A400,and A500 may also be configured for use with the eye bolts A632, handlesA634 and cable A636.

In alternative embodiments, the handles A634 may not be used. A singleeye bolt A632 may also be formed integral with a single component A614.A single cable A636 may also be used through each of the eyebolts A632.Each cable A636 would independently attach to the external surface 604of the fluid end body A602.

Several kits are useful for assembling the fluid end A600. A first kitcomprises a plurality of the components 614, a plurality of the retainerelements A620, and the fastening system A626. The kit may be assembledusing the fluid end body A602.

With reference to FIGS. 80-93, a single fluid end body may use anycombination of the kits described herein. The fluid end bodies,components, and retainer elements described herein may be made of highstrength steel.

While the fluid end bodies A102, A202, A302, A402, and A502 shown inFIGS. 80-92 are substantially rectangular in shape, the kits describedherein may also be used with any shape of a fluid end body, such as thatshown in FIG. 93. Likewise, the retainer elements described herein mayvary in shape and size, as desired. For example, the circular retainerelements described herein may be square or rectangular shaped.

The fastening systems A134, A222, A320, A420, and A522 described hereineach use eight studs around each bore opening. In alternativeembodiments, more than eight studs or less than eight studs may be usedto secure each retainer element over each bore opening. For example,FIG. 93 only shows six studs securing each retainer element A620 overeach bore opening A610. Likewise, fewer than 16 or more than 16 screwsmay be used with the fastening systems A178, A260, A352, and A444. Thenumber of peripheral openings formed in each retainer element describedherein may correspond with the number of openings formed around eachbore opening in each fluid end body and the number of studs or screwsbeing used.

The fastening systems described herein reduce the amount of torquerequired to secure each retainer element to the fluid end bodies. Ratherthan having to torque one large retaining nut, the torque is distributedthroughout the plurality of studs, nuts, or screws. Decreasing theamount of torque required to seal the bores increases the safety of theassembly process.

Turning to FIG. 94, a stud A700 is shown. The stud A700 may be used withthe fastening systems A134, A222, A320, A420, A522, and A626 shown inFIGS. 80, 83, 86, 88, 90, and 93. For exemplary purposes, the stud A700will be described with reference to fluid end A100, shown in FIG. 80.

The stud A700 has a first threaded section A702 and an opposite secondthreaded section A704. The threaded sections A702 and A704 are joined byan elongate, cylindrical body A706. The first threaded section A702 isconfigured for threading into one of the plurality of threaded openingsA144 formed in the fluid end body A102. The second threaded section A704is configured for threading into the threaded opening formed in one ofthe nuts A152.

The first section A702 may have fewer threads than that of the openingA144. For example, if the opening A144 has 18 internal threads, thefirst section A702 of the stud A700 may only have 16 external threads.This configuration ensures that all of the threads formed on the firstsection A702 will be engaged and loaded when the first end A702 isthreaded into the opening A144. Engaging all of the threads helpsincrease the fatigue life of the first end A702 of the stud A700.Likewise, the second section A704 may have fewer external threads thanthere are internal threads formed in the nut A152. The stud A700 mayalso be subjected to shot peening on its non-threaded sections prior toits use to help reduce the possibility of fatigue cracks. The stud A700may have a smooth outer surface prior to performing shot peeningoperations.

The body A706 of the stud A700 comprises a first section A708 and asecond section A710. The first section A708 has a smaller diameter thanthe second section A710. The retainer element A132 is primarily held onthe first section A708 of the stud A700. The diameter of the secondsection A710 is enlarged so that it may center the washer A150 on thestud A700.

The diameter of the second section A710 is configured so that it is onlyslightly smaller than the diameter of the central opening of the washerA150. This sizing allows the washer A150 to closely receive the secondsection A710 of the stud A700 when the washer A150 is positioned on thestud A700. When the washer A150 is positioned on the second sectionA710, the washer A150 is effectively centered on the stud A700. Thewasher A150 is also effectively centered against the nut A152, once thenut A152 is installed on the stud A700.

Without placing the washer A150 on the second section A710, the washermay have to be manually centered on the stud A700 prior to installingthe nut A152. If the washer A150 is not properly centered on the studA700 or against the nut A152, it may be difficult to effectively torqueor un-torque the nut A152 from the stud A700, depending on the type ofwasher used.

FIGS. 95-102 illustrated another fluid end configuration, aspects ofwhich may be employed in combination with the embodiments of FIGS. 1-94.Reference is made here to the reference indicators used in FIGS. 80-82,but the embodiments discussed below are also applicable to thecorresponding portions of FIGS. 83-94. Like embodiments discussed above,the configuration shown in FIGS. 95-102 includes removable retainerelements A132 that are secured to the fluid end body A102 with afastening system that includes, for example, eight nuts A152 and washersA150 arranged around the perimeter of the retainer element A132. As canbe seen with respect to FIG. 101, however, the retainer elements A132respectively include internally-threaded bores A106 and A108 configuredto receive respective externally-threaded retainer nuts.

In this embodiment, to access a given fluid end bore A106, A108 (e.g.,to perform field maintenance), a technician may first attempt to removethe retainer nut. If the retainer nut can successfully be removed andreplaced, then interior access to the fluid end A100 may be accomplishedwithout having to remove and replace the several fastening elements thathold the retainer element A132 in place. Accordingly, accessing thefluid end interior via the retainer nut rather than by removing theretainer element may take less time and may provide fewer opportunitiesfor technician error (e.g., by reducing opportunities to incorrectlythread or apply incorrect torque to the fasteners).

As with many surfaces exposed to the harsh interior environment of thefluid end A100, however, the surfaces between the retainer nut and theretainer element A132 may become a point of failure. For example, thethreads may foul during operation such that the retainer nut cannotreadily be removed in the field, or erosion may cause leakage to occuraround the threads. If the retainer nut were threaded directly into thebody of the fluid end, such a failure would likely not be repairable inthe field—necessitating transport of the fluid end for service—and inthe worst case, could result in the loss of the entire fluid end. Bythreading the retainer nut into the removable retainer element A132,however, many instances of thread failure can be repaired by simplyremoving and replacing the retainer element A132 and retainer nut. Suchan operation could readily be performed in the field, reducing fluid enddowntime. Moreover, the cost of replacing the removable retainer elementA132 and retainer nut is considerably less than replacing the entirefluid end A100, reducing cost of operations.

Appendix B: Tapered Valve Seats

The following paragraphs will discuss valve seats for use, for example,with the fluid end of FIGS. 80-94. For the purposes of the followingdescription of FIGS. 103-110, reference numerals exclusive to thoseFIGS. will be used.

With reference to FIGS. 103, 104 and 107, shown therein is a fluid endB100. A fluid end B100 is the flow control sub-assembly of ahigh-pressure reciprocating piston pump. Pumps of this type are used inthe oil industry to provide high pressure for tasks such as drilling,formation stimulation, also known as fracking, and completed wellservicing. They are often referred to as high pressure hydraulicfracturing pumps. The most common design of such a pump includes twosub-assemblies, the power end (not shown) and the fluid end 100.

The power end converts the rotational input of a drive source to thereciprocating linear motion of pistons B170, usually with a crankshaftarrangement. The internal components of the power end are enclosed in arelatively clean, lubricated environment and have a much longer servicelife than the components of the fluid end.

The fluid end B100 controls the flow of the fluid pressurized by thepistons B170. The pistons B170 are attached to the crank rods of thepower end. The sealing integrity of fluid ends must withstand not onlyhigh operating fluid pressures, presently 15,000 pounds per square inchand higher, but also must do so while controlling the flow of corrosiveand/or abrasive fluids that are notorious for eroding the internalcomponents of typical fluid ends. This abrasiveness and/orcorrosiveness, combined with high flow rates used in standard service,dramatically shorten the life of typical fluid ends when compared tothat of typical power ends.

Fluid ends B100 typically have from two to five or more identicalsections consisting of components that accomplish the purpose describedabove. Each fluid end comprises valves B104. The valves B104 control theinlet of low pressure fluid and outlet of high pressure fluid from eachfluid end B100 section.

The valves B104 are typically identical and are an assembly that has abody B120, a return mechanism, such as a spring B112, and a sealing faceB114 formed on the body. The valves B104 are positioned within the inletand outlet sections to control fluid flow in and out of the fluid endB100. As shown in FIGS. 94, 103 and 107, the valve B104 is in an inletsection B102 of the fluid end B100.

Each sealing face B114 seals against a valve seat. A valve seat istypically a tube that has been hardened, or is made of harder materialthan the fluid end, that is installed in the inlet and outlet sectionsof the fluid end. The valve seat and provides a hardened sealing surfacefor the sealing face B114 of the valve B104 to seal against. Without thehardened sealing surface of the valve seat the area would quickly erodereducing the service life of the fluid end.

Recent developments in the energy exploration industry require anincreased maximum sustained pressure in pumps from around 8,000 psi to15,000 psi or more with expected maximum spikes up to 22,500 psi. Thisincrease in maximum pressure causes failures in components not seen atlower pressures. Typical failures now include the failure of valves dueto erosion of the valve sealing face 114 and seat sealing face 118 whichis accelerated by the large closing forces of the valve sealing faceagainst the valve seat sealing face. When either sealing face failsleakage occurs around the component. Leakage reduces the maximumpressure and flow capabilities of the system. Leakage of an abrasivefluid at such high pressures quickly erodes the area requiring repair orreplacement of the entire fluid end. A fractured fluid end body isalways a catastrophic failure requiring replacement.

Efforts to eliminate the erosion of the valve sealing face have includedhardening both sealing faces. The mating hardened surfaces provide animproved seal and allow the system to operate as desired. However, theimpact of the hardened valve sealing face against the valve seat sealingface increases the erosion rate of both surfaces due to the closingforce imparted to the valve by the valve return spring and the internalpressures of the fluid end. This failure occurs in an unacceptably shorttime requiring repair or replacement of the valve and/or the valve seat.Improvements are needed in the internal sealing of fluid ends toincrease operating life while reducing downtime and operating cost.

With reference to FIG. 103, fluid end B100 comprises a prior art valveseat B108. The inlet passage, or port B102 is shown with the valve B104in the closed position. The valve B104 body B120 has an alignmentstructure B106 and a protrusion B110. The alignment structure B106assists in maintaining proper valve B104 orientation to a valve seatB108 when in operation. Protrusion B106 centers a coil spring B112 thatis typically used to apply a closing force to the valve B104 duringoperation. When the valve B104 is closed by the coil spring B112, thevalve sealing face B114 contacts the valve seat B108.

The valve seat B108 is installed in the inlet port B102. Typically, thevalve seat B108 is precisely machined to fit in the fluid end B100. Thisfit may be close enough to prevent the gap between the seat B108 andfluid end B100 from leaking. It is typical to have a seal located in aseal groove B122 on the outside diameter of the seat B108 to keep thejoint from leaking. The valve seat B108 is installed by inserting itinto an appropriately sized fluid passage bore B150 in the inlet portB102 of the fluid end B100. The valve seat B108 has a tapered flangeB130. The valve seat flange B130 bottoms out on the valve seat boreB150.

The seat B108 defines a sealing surface B118 that is complementary tothe sealing surface B114 of the body B120. The valve sealing surfaceB114 contacts the seat sealing surface B118 stopping fluid flow.

The valve seat flange B130 resists the tendency of the valve seat B108to be driven deeper into the inlet port B102 by the forces produced bythe fluid end. These flanges B130 typically form the upper portion of avalve seat B108. As shown, the flange B130 meets the remainder of thevalve seat B108 at a transition point B124. The transition point B124may be the apex of a ninety degree to one hundred eighty degree externalangle on the outer surface of the valve seat B108. In all such valveseats B108, the transition point has an external angle of less than onehundred eighty degrees.

There is a stress concentration at the transition point B124 which is atypical failure point. Attempts to reduce the stress concentration byadding a stress relief groove have been unsuccessful. A sharp transitionat the flange additionally produces a stress concentration in the fluidend B100 body and increases the likelihood of cracking the internal wallof the fluid end Moo body in that area. Typically, the wall thickness ofthe fluid end 100 body has been increased in this area to reduce thesefailures however size and cost restraints prevent adequate increases inthe wall thickness.

The sealing surface B114 may be hardened by a post manufacturingprocess, such as nitriding or flame hardening, or is manufactured from ahard material such as carbide. It is advantageous to have the hardenedvalve sealing surface B114 to minimize erosion. Seat B108 may also havethe seat sealing surface B118 hardened by a post manufacturing processlike those performed on the valve sealing surface B114. However, thepress fit or close fit method of installation combined with the residualstresses from the post manufacturing process make it extremely difficultto install the seat B108 without breaking it. Because of theseinstallation difficulties, seat B108 is typically made entirely ofcarbide or some other hard material thus reducing, but not eliminating,installation difficulties.

A valve insert B116 may be placed in the body B120 at the sealingsurface B114, and may be either permanently attached or replaceable. Thevalve insert B116 can be made of any of a number of elastomericmaterials. The purpose of valve insert B116 is to provide more sealingcapability for the valve B104. While the primary sealing is accomplishedby the metal to metal contact of the valve sealing surface B114 to theseat sealing surface B118, it is advantageous to have the elastomericmaterial encapsulate and seal around any solids trapped between thevalve insert B116 and the seat sealing surface B118.

During operation the valve B104 reciprocates axially between open andclosed positions. In the open position fluid flow occurs and in theclosed position fluid flow is blocked. As the valve B104 moves from theopen position to the closed position the valve insert B116 contacts theseat sealing surface B118 first and deforms around any trapped solids.Once the valve insert B116 deforms, or compresses, axially the valvesealing surface B114 contacts the seat sealing surface B118 and stopsmoving. Erosion occurs with each cycle in large part due to the impactof the valve sealing surface B114 on the seat sealing surface B118.

The repeated impacts of both sealing surfaces B114, B118 erode only inthe area that the two surfaces B114, B118 contact each other and aretypically the point of failure. Repair of the fluid end B100 requiresthe replacement of both the valve B104 and the seat B108. Thereplacement cost of a carbide seat B108 is very expensive and theindustry can benefit from an improvement that reduces this cost.

With reference to FIG. 104-106B, the fluid end 100 contains an improvedvalve seat B302. The valve seat B302 has no flange B130 (FIG. 103).Rather, as best shown in FIGS. 105A and 18B, the valve seat has a bodyB304 with an annular ring portion B306 and a tapered lower portion B312.The annular ring portion B306 has an outer surface B308 that issubstantially cylindrical and an inner surface B310 that issubstantially complementary to a cylinder. A slight taper may be used onthe outer surface B308 of the annular ring portion B306.

A seat sealing surface B314 is disposed at a first extremity of theannular ring portion. The sealing surface B314 is complementary to thevalve sealing surface B114 of the valve B104 body B120.

The tapered lower portion B312 generally is defined by a continuation ofthe inner surface B310, but having a tapered outer surface B316. Theinternal bore B150 has an internal taper B152 that corresponds to thetapered portion B312 of the valve seat B302 body B304. The tapered outersurface B316 and outer surface B308 meet at a transition point B350. Thetransition point B350 has an external angle of greater than one hundredeighty degrees. Thus, the transition point B350 has reduced stress ascompared to that of the prior art.

The tapered portion B312 terminates at a bottom surface B320 of thevalve seat B302. As shown, the bottom surface B320 does not contact theinternal bore B150 of the fluid end B100. Thus, the force appliedthrough the valve seat B302 to the fluid end B100 body is provided atthe internal taper B152 of the internal bore B150. The geometry of valveseat B302 eliminates any transition that would provide a stressconcentration point thus increasing the service life of the valve seatB302. Stress applied through the valve seat B302 is evenly distributedon internal taper B152 and tapered outer surface B316, rather than beingconcentrated at a transition.

FIGS. 106A and 106B show an alternative valve seat B402. The valve seatB402 is largely identical to seat B302, but the tapered portion B312 hasa tapered inside diameter B403. The tapered inside diameter B403 tendsto reduce turbulent flow within the valve seat B402, reducing erosion onthe inner surface B310 of the seat B402.

With reference to FIG. 107, an alternative valve B204 and valve seatB208 are shown in an inlet port B102 of the fluid end B100. The valveseat B208 has generally the same geometry as valve seats B302, B402.However, valve seat B208 comprises an insert B220 disposed in the seatsealing surface B218.

The valve B204 comprises a valve sealing surface B214. The valve sealingsurface B214 may be hardened by a post manufacturing process, such asnitriding or flame hardening, or may alternatively be manufactured froma hard material such as carbide. It is advantageous to have the hardenedvalve sealing surface B214 to minimize erosion. The area of the valvesealing surface B214 is larger than that of typical valves, such as thepreviously attempted solution described above. The larger surface B214distributes the impact force about a greater area, reducing the impactforce at any particular point on the two sealing surfaces B214, B218.Distributing the closing force reduces the amount of erosion caused bythe impact force.

A valve insert B216, made of a deformable elastomeric material, may beformed on a portion of the valve sealing surface B214. Valve insert B216may be similarly formed to insert B116 in FIG. 103, or other knowninserts.

In one embodiment, the valve seat B208 is made of stainless steel orother corrosion resistant material. Typically, however, such material isnot hard enough to adequately protect against erosion. Therefore, theseat insert B220 is made of a hardened material, such as tungstencarbide, to resist erosion at the location of repeated contact with thevalve sealing surface B214. Seat insert B220 is installed in seat B208and retained by interference fit, a taper lock design or the like. Theinsert B220 defines a seat insert sealing surface B222 that iscomplementary to the valve sealing surface B214.

During operation the valve B204 reciprocates axially between open andclosed positions. In the open position fluid flow occurs and in theclosed position fluid flow is blocked. As the valve B204 moves from theopen position to the closed position the valve insert B216 contacts theseat sealing surface B218 first and deforms around any trapped solids.Once the valve insert B216 deforms, or compresses, axially the valvesealing surface B214 contacts the seat insert sealing surface B222 andstops moving.

As shown in FIGS. 108A-108C, the seat insert B220 may be characterizedby different shapes. The seat insert B220, at the top cylindricalportion, has a larger outer diameter. The sum of the seat insert sealingsurface B222 and the seat sealing surface B218, has a larger surfacearea than conventional valve seats. As discussed with respect to valvesealing surface B214 area, the larger area allows for less force perunit area between the sealing surfaces B214, B218, B222 without reducingthe closing force. An additional advantage of the increased outerdiameter is that the seat insert B220 may now be installed withoutdecreasing the seat B208 wall thickness to a point where prematurefailure of the seat B208 will occur.

Additional embodiments are shown in FIGS. 108B and 108C. Theseembodiments illustrate variations in the installation and retentionmethods of the seat insert B220 in the seat B208.

Any seat B208 having a separate component that is harder than the basematerial of the seat and is approximately complementary to the valvesealing surface B218 is contemplated. For instance, the seat insert B220could be the outer diameter of the seat B208 and the inner diameter usedto attach the seat insert to the seat by threading, interference fit orthe like. This would require the valve sealing surface to also be theouter diameter portion of the valve and the valve insert to be the innerportion of the valve.

As shown in FIGS. 109A and 109B, a valve seat B500 has an outer surfaceB504 that may not match the bore B150 of the fluid end B100 precisely.In this embodiment, a valve seat B500 has an annular ring portion B502with an outer surface B504 and a tapered portion B505 with a taperedportion outer surface B506. The outer surface B504 of the valve seatB500 differs from that of FIG. 104 and FIG. 107, as the angle of theouter surface relative to the internal bore 150 changes more than oncealong its length. Further, the outer surface B504 only partiallyconforms to the internal bore B150.

In one embodiment, a first outer surface section B510 and a second outersurface section B512 meet at an angle at transition B514. TransitionB514 is generally disposed on a curve around the external surface B504of the seat B500. It should be understood that the valve seat B500generally conforms to the bore B150 at the second outer surface sectionB512 and abuts the bore when seated. In one embodiment, the second outersurface section may be press fit against the bore B150.

As shown best in FIG. 109B, the change in the taper of outer surfaceB504 at the transition B514 causes the fully seated valve seat B500 todefine a gap B520 between the first outer surface section B510 and thebore B150. In one embodiment, the first outer surface section B510 maybe offset from the bore B150 by less than 5 degrees. This angle may beless than one degree. It should be understood that the external anglebetween the first outer surface section B510 and the second outersurface section B512 at the transition B514 is just greater than onehundred eighty degrees. In one embodiment, the external angle attransition B514 is between one hundred eighty and one hundred ninetydegrees.

The second outer surface section B512 and the tapered portion outersurface B506 both fully seat against the bore B150. However, gap B520reduces the tendency of the valve seat B500 to become lodged within thefluid end B100 after repeated impacts between the valve seat B500 andthe valve body B120. Therefore, the small gap B520 dramatically improvesthe ease of removal and replacement of the valve seat B500.

Thus, in the embodiment of FIG. 110, the valve seat B500 comprises atapered portion B505, an intermediate portion B540, and a strike faceportion B545, each defined by the shape of its outer surface. Generally,a transition point B350 defines the boundary between the tapered portionB505 and intermediate portion B540, while the transition B514 definesthe boundary between the intermediate portion B540 and strike faceportion 545.

First, the tapered portion B505 is defined by the tapered portion outersurface B506 and an inner surface B550. The inner surface B550 maycomprise a surface complementary to the outer surface of a cylinder, ormay have an inverse tapered portion or bevel B552 as shown. The innersurface B550 and tapered portion outer surface B506 terminate at theflat bottom surface B320. In the embodiment of the valve seat B500 shownin FIG. 109A, the entire tapered portion outer surface B506 engages thebore B150. None of the bottom surface B320 seats on the bore B150.

Second, the intermediate portion B540 is defined by the inner surfaceB550 and the second outer surface section B512. The intermediate portionshould be of substantially constant thickness, outer diameter, and innerdiameter; though a minor taper from the transition B514 to thetransition B350 may exist. The taper of the intermediate portion B540 issignificantly less per unit length than the taper of the tapered portionB505.

Third, the strike face portion B545 is defined by the inner surfaceB550, including a portion of the insert B530 that conforms to the innersurface, and the first outer surface section B510. The strike faceportion B545 has a strike face B535 which conforms to a surface of thevalve body B120. A recess B555 conforms to the insert B530 for seatingthe same. The portion of the insert B530 forms a part of the strike faceB535.

The strike face B535 and inner surface B550 both include, in part, theinsert B530. The insert B530 conforms to adjacent surfaces along thestrike face B535 and inner surface B550. In the embodiment of FIG. 110,the insert B530 is only disposed in the strike face portion B545. In theembodiment of FIG. 110, the first outer surface section B510 issubstantially cylindrical in shape while the adjacent bore B150 has aslight taper (roughly matching second outer surface section B512).Therefore, the strike face section B545 does not contact the bore B150,forming gap B520 (FIG. 109B).

Modifications to this geometry could be made, for example, if the boreB150 abutting the annular ring section B502 is complementary to acylinder, the first outer surface section B510 could taper slightlyinward to generate gap B520.

The strike face portion B545 does not engage the bore B150 at any point.Thus, all bore engagement between the valve seat B500 and bore B150takes place at the tapered portion B505 and intermediate portion B540.

As shown best in FIG. 110, the entire valve seat B500, inclusive of theinsert B530, is ring-shaped, and is defined by a cross-section that hasno concave angles. Eliminating concave angles enhances the strength ofthe valve seat and prevents failure at weak points, such as the weakpoint at transition B130 (FIG. 103).

Appendix C: Stem Guided Valves

In FIGS. 111-124, an embodiment of a stem guided valve is shown. Such avalve may be used with the tapered valve seat (Appendix B) and in thefluid end described herein. For the purposes of the followingdescription of FIGS. 111-124, reference numerals exclusive to thoseFIGS. will be used.

With reference to FIGS. 111-113, a fluid end body C100 having an inletport C102, a discharge port C104, a plunger port C106, and a serviceport C108 is shown. An outlet port C109 is positioned adjacent thedischarge port C104. Fluid enters the fluid end body C100 through theinlet port C102 and exits through the outlet port C109. The plunger portC106 contains a plunger (not shown) to pump fluid through the fluid endbody C100. The ports C102, C104, C106, and C108 each open into boresthat join at a pressure chamber C112.

A first male stem guided valve C110 having a central axis x-x is shownpositioned above the inlet port C102 in FIGS. 111 and 113. The valveC110 seals against a valve seat C111. The valve seat C111 has a centralopening that is concentric with the inlet port C102. The valve C110 hasa sealing surface C114 formed on its bottom, and the valve seat C111 hasa sealing surface C116 formed on its top. When the surfaces C114 andC116 engage, the valve C110 blocks fluid from passing from the inletport C102 to the pressure chamber C112. The valve C110 is considered inthe closed positioned when the sealing surfaces C114 and C116 areengaged.

The valve C110 is shown in the open position in FIGS. 111 and 113. Thevalve sealing surface C114 is axially spaced from the seat sealingsurface C116 in the open position. Fluid may flow through the inlet portC102, around the valve C110 and into the pressure chamber C112 when thevalve C110 is in the open position.

The valve C110 has a stem C118 projecting from its top opposite itssealing surface C114. A valve retainer C122 may be positioned in thefluid body C100 above the stem C118. The valve retainer C122 has aU-shape. The top edges of the retainer C122 sit within a valve grooveC123 formed in the walls of the fluid end body C100, as shown in FIG.C26. A guide bore C120 is formed within the valve retainer C122. Theguide bore C120 opens on opposite sides of the bottom of the retainerC122. As best shown in FIG. 113, the stem C118 may extend entirelythrough the bore C120 and project out of the top surface of the retainerC122. The stem C118 may be received within in the guide bore C120 of thevalve retainer C122. In operation, the stem C118 may move axially alongaxis x-x within the guide bore C120. The guide bore C120 operates tomaintain the orientation of the valve sealing surface C114 relative tothe seat sealing surface C116. Because the bore C120 is open on bothends, any fluid within the bore may drain from the bore duringoperation.

A spring C124 is shown in FIG. 111 positioned on the top side of thevalve C110. The spring C124 is not shown in FIG. 113 for clarity. Theforce applied by the spring C124 to the top of the valve C110 biases thevalve C110 to the closed position. The position of valve Clio isdetermined by the difference in fluid pressure between the inlet portC102 and the fluid chamber C112. The valve C110 will be open if theforce applied to the bottom of the valve C110 due to fluid pressure atthe inlet port C102 is greater than the force applied to the top of thevalve C110 due to fluid pressure in the chamber C112 plus the additionalforce applied by the spring C124. In contrast, the valve C110 will beclosed when the force applied to the bottom of the valve C110 due tofluid pressure at the inlet port 102 is less than the force applied tothe top of the valve C110 due to fluid pressure in the chamber C112 plusthe additional force applied by the spring C124.

With reference to FIGS. 11 and 112, a second male stem guided valve C210having a central axis y-y is shown positioned within the bore below thedischarge port C104. Axis y-y may be collinear with axis x-x of valveC110 but is not required to be. The discharge port C104 is shown sealedby a discharge plug C226. The valve C210 is shown in the closedposition. When in the closed position, the valve C210 blocks fluid fromexiting the fluid end body C100 through the outlet port C109.

Like valve C110, valve C210 seals against a valve seat C211. The valveseat C211 has a central opening that opens into the chamber C112. Thevalve C210 has a sealing surface C214 formed on its bottom and the valveseat C211 has a sealing surface C216 formed on its top. The valvesealing surface C214 is in contact with the seat sealing surface C216 inthe closed position.

The valve C210 has a stem C218 projecting from its top opposite sealingsurface C214. A guide bore C220 is formed in the discharge plug C226.The stem C218 may be received within the guide bore C220. In operation,the stem C218 may move axially along its y-y axis within the guide boreC220. The guide bore C220 and the stem C218 operate to maintain theorientation of the valve sealing surface C214 relative to the seatsealing surface C216.

A spring C224 is shown in FIG. iii positioned on the top side of thevalve C210. The spring is not shown in FIG. 112 for clarity. The forceapplied by the spring C224 to the top of the valve C210 biases the valveC210 to the closed position. The position of valve C210 is determined bythe difference in fluid pressure between the outlet port C109 and thefluid chamber C112. The valve C210 will be open if the force applied tothe bottom of the valve C210 due to fluid pressure in the chamber C112is greater than the force applied to the top of the valve C210 due tofluid pressure in the outlet port C109 plus the additional force appliedby the spring C224. In contrast, the valve C210 will be closed when theforce applied to the bottom of the valve C210 due to fluid pressure inthe chamber C112 is less than the force applied to the top of the valveC210 due to fluid pressure at the outlet port C109 plus the additionalforce applied by the spring C124.

In operation, fluid may enter the guide bore C220 formed in thedischarge plug C226. The fluid may reduce the range of motion of thestem C218 within the guide bore C220. A decrease in the range of motionof the stem C218 may lead to restricted fluid flow throughout the fluidend body C100, erosion of the bore walls C220 and the stem C218, and thepossible failure of components within the fluid end C100. To preventfluid build-up within the bore C220, at least one relief bore C228 maybe formed in the discharge plug C226. The relief bore C228 drains fluidfrom the bore C220 during operation. The relief bore C228 opens in theguide bore C220 and opens in the outlet port C109. Two relief bores C228are shown in FIGS. 111-112. The relief bores C228 are positioneddiagonally within the plug C226. However, other configurations of boresmay be used.

Turning now to FIGS. 114 and 116, a first female stem guided valve C310having a central axis x-x is shown. The valve C310 is positioned withina bore above the inlet port C102. The fluid end body C100 and portsC102, C104, C106, C108, and C109 are identical to those of FIG. 111. Thevalve C310 seals against a valve seat C311 in the same manner as valveC110 and valve seat Cm. The valve C310 is shown in the open position inFIGS. 114 and 116.

A guide bore C320 is formed in the body of the valve C310. The guidebore C320 opens on the top of the valve C310. A valve retainer C322 isshown positioned within the fluid body C100 above the guide bore C320.The valve retainer C322 has a U-shape. The top edges of the retainerC322 sit within a valve groove C323 formed in the walls of the fluid endbody C100, as shown in FIG. 116.

A stem C318 is connected to or formed integral with the valve retainerC322. The stem C318 shown in FIGS. 114 and 116 is threaded to theretainer C322. The stem C318 projects downward towards the valve C310and may be received within the bore C320. A stem vent C330 is connectedto or formed integral with the top of the stem C318. The stem vent C330projects upward away from the valve C310. As the valve C310 movesaxially along its x-x axis between the open and closed positions theguide bore C320 also moves axially relative to the stem C318. The guidebore C320 and the stem C318 operate to maintain the orientation of thevalve C310 relative to the valve seat C311. A spring C324 is shown inFIG. 114 positioned on the top of the valve C310. The spring C324operates identically to spring C124. The spring C324 is not shown inFIG. 116 for clarity.

In operation, fluid may enter the guide bore C320 formed in the valveC310 and cause the same issues noted with regard to valve C210. Toprevent fluid build-up within the bore C320, a relief port C328 may beformed in the stem C318 that joins a cross-bore C332 formed in the stemvent C330. The cross-bore C332 may be perpendicular to the relief portC328 and open on opposite sides of the stem C318. Fluid within the boreC320 may enter the relief port C328 and exit the stem through thecross-bore C332. After exiting the stem C318 through the cross-boreC332, fluid may flow towards the chamber C112.

With reference to FIGS. 114 and 115, a second female stem guided valveC410 with a central axis y-y, which may be collinear with axis x-x butis not required to be, is shown positioned within the bore below thedischarge port C104. The discharge port C104 is shown sealed by adischarge plug C426. The valve C410 seals against a valve seat C411 inthe same manner as valve C210 and seat C211. The valve C410 is shown inthe closed position.

A guide bore 420 is formed in the body of the valve C410. The guide boreC420 opens on the top of the valve C410. A stem C418 is connected to orformed integral with the discharge plug C426. The stem C418 shown inFIGS. 114-115 is press fit into a bore formed in the discharge plugC426. The stem C418 projects downward towards the valve C410 and may bereceived within the guide bore C420. As the valve C410 moves axiallyalong its y-y axis between the open and closed positions the guide boreC420 also moves axially relative to the stem C418. The guide bore C420and the stem C418 operate to maintain the orientation of the valve C410relative to the valve seat C411. A spring C424 is shown in FIG. 114positioned on the top of the valve C410. The spring C424 operatesidentically to spring C224. The spring C424 is not shown in FIG. 115 forclarity.

In operation, fluid may enter the guide bore C420 formed in the valveC410 and cause the same issues noted with regard to valve C210. Toprevent fluid build-up within the bore C420, a relief port C428 may beformed in the stem C418 that opens into a chamber C430 formed in thedischarge plug C426. The chamber C430 is in fluid communication with across-bore C432 formed in the plug C426. The cross-bore C432 may beperpendicular to the relief port C428 and open on opposite sides of thedischarge plug C426. Fluid within the bore C420 may enter the reliefport C428 and exit the plug C426 through the cross-bore C432. Afterexiting the plug C426 through the cross-bore C432, fluid may flowtowards the outlet port C109.

Turning to FIGS. 117, 118 and 120, a first female stem guided valve C510having a central axis x-x is shown. The valve C510 is positioned withina bore above the inlet port C102. The fluid end body C100 and portsC102, C104, C106, C108, and C109 are identical to those of FIGS. 111 and114. The valve C510 seals against a valve seat C511 in the same manneras valve C310 and valve seat C311. The valve C510 is shown in the openposition.

A guide bore C520 is formed in the body of the valve C510. The bore C520opens on the top of the valve C510. A guide C534 is positioned withinand attached to the bore C520. The guide C534 shown in FIGS. 117, 118and 120 is threaded to the inner surface of the bore C520. The guideC534 projects upwards from the top of the valve C510 and has a centralbore C530.

A valve retainer C522 is shown positioned within the fluid body C100above the guide C534. The valve retainer C522 has a U-shape. The topedges of the retainer C522 sit within a valve groove C523 formed in thewalls of the fluid end body C100, as shown in FIG. 30. A stem C518 isconnected to or formed integral with the valve retainer C522. The stemC518 shown in FIGS. 117 and 120 is press fit into a bore formed in theretainer C522. The stem C518 projects downward towards the valve C510and may be received within the central bore C530 of the guide C534. Asthe valve C510 moves axially along its x-x axis between the open andclosed positions the central bore C530 also moves axially relative tothe stem C518. The guide C534 and the stem C518 operate to maintain theorientation of the valve C510 relative to the valve seat C511. A springC524 is shown in FIG. 117 positioned on the top of the valve C510. Thespring C524 operates identically to spring C124. The spring C524 is notshown in FIGS. 118 and 120 for clarity.

In operation, fluid may enter the guide C534 attached to the valve C510and cause the same issues noted with regard to valve C210. To preventfluid build-up within the central bore C530 of the guide C534, a seriesof ports C536 may be formed in the guide C534. While ports C536 areshown to be circular in this embodiment any shape of port can be used.Fluid within the central bore C530 may pass through the ports C536formed in the guide C534. After exiting the ports C536, the fluid mayflow towards the chamber C112.

In operation, the stem C518 may be prevented from moving the entirelength of the bore C530 by an annular shoulder C531 formed in the guideC534. This allows the portion of the bore C530 positioned below theshoulder C531 to accumulate fluid or other particles prior to drainingthe fluid and particles through the ports C536.

With reference to FIGS. 117-119, a second female stem guided valve C610having a central axis y-y, which may be collinear with axis x-x but isnot required to be, is shown positioned within a bore below thedischarge port C104. The discharge port C104 is shown sealed by adischarge plug C626. The valve C610 seals against a valve seat C611 inthe same manner as valve C410 and seat C411. The valve C610 is shown inthe closed position.

A guide bore C620 is formed in the body of the valve C610. The guidebore C620 opens on the top of the valve C610. A guide C634 is positionedwithin and attached to the bore C620. The guide C634 is identical to theguide C534. The guide C634 has a central bore C630 and at least one portC636 formed in its sides.

A stem C618 is connected to or formed integral with the discharge plugC626. The stem C618 shown in FIGS. 117 and 119 is threaded into a boreformed in the discharge plug C626. The stem C618 projects downwardtowards the valve C610 and may be received within the central bore C630of the guide C634. A plurality of ports C636 are formed in the guideC634. Fluid within the bore C630 may pass through the guide C634 thesame way fluid passes through the guide C534.

Turning to FIGS. 121, 122, and 124, a first female stem guided valveC710 having a central axis x-x is shown. The fluid end body C100 andports C102, C104, C106, C108, and C109 are identical to those of FIGS.111, 114, 117. The valve C710 seals against a valve seat C711 in thesame manner as valve C510 and seat C511. The valve C710 is shown in theopen position.

A guide bore C720 is formed in the body of the valve C710. The bore C720opens on the top of the valve C710. A guide C734 is positioned withinand attached to the bore C720. The guide C734 shown in FIGS. 121, 122,124 is threaded to the inner surface of the bore C720. The guide C734projects upwards from the top of the valve C710 and has a central boreC730. The guide C734 is identical to guide C534 except that instead ofhaving ports C536 formed in the guide C534, the guide C734 has aplurality of slots C736 formed in it. A retainer C722 is positioned inthe fluid end body C100 above the valve C710. The retainer C722 isidentical to retainer C522. A stem C718 is attached to the retainerC722. The stem C718 is identical to stem C518. Fluid is drained from thevalve C710 and stem C718 the same way fluid is drained from valve C510.

In FIGS. 121-123, a second female stem guided valve C810 having acentral axis y-y is shown. The valve C810 seals against a valve seatC811 in the same manner as valve C610 and seat C611. The valve C810 isshown in the closed position.

A guide bore C820 is formed in the body of the valve C810. The bore C820opens on the top of the valve C810. A guide C834 is positioned withinand attached to the guide bore C820. The guide C834 is identical toguide C634 except that instead of having ports C636 the guide C834 has aplurality of slots C836 formed in it. A discharge plug C826 ispositioned above the valve C810. The discharge plug C826 is identical todischarge plug C626. A stem C818 is attached to the plug C826. The stemC818 is identical to stem C618. Fluid is drained from the valve C810 andguide C834 the same way fluid is drained from valve C610.

Enhancements such as the hardening of any or all contact surfaces of thestem, guide, and guide bore may reduce wear and increase life. Bushings,bearings, or any other replaceable wear items that can mitigate wear orprolong life could be used in the interface between the stem and guidebore. This includes replaceable wear rings such as elastomeric O-ringsor the like. The stems, valves, or components described herein may alsobe formed from tungsten carbide or be coated or sprayed with tungstencarbide to help reduce wear over time.

Numerous methods to connect the stems to serviceable portions of thefluid end assembly may be used such as threading, press fit, welding,brazing or the like. There are also numerous ways to produce a guidebore in the appropriate component whether by producing separatecomponents or making the bore integral. The ports described herein mayalso take on different shapes and sizes.

Appendix D: Valve Having Dual Inserts

The insert in the valve bodies shown in FIGS. 125-130 may be used withthe fluid end described herein and the valve bodies and valve seatarchitecture previously discussed. For the purposes of the followingdescription of FIGS. 125-130, reference numerals exclusive to thoseFIGS. will be used.

With reference to FIGS. 125 and 126, a fluid end D100 is shown. Thefluid end Dino comprises a fluid end body D102 having a plurality offirst and second bores D106, D108 formed adjacent one another therein,as shown in FIG. 125. The number of first bores D106 usually equals thenumber of second bores D108. Each first bore D106 intersects its pairedsecond bore D108 within the fluid end body D102 to form an internalchamber D112, as shown in FIG. 125.

FIG. 125 shows five first and second bores D106, D108. In alternativeembodiments, the number of sets of paired first and second bores in thefluid end body may be greater than five, or less than five.

Each bore of each set of paired bores D106 and D108 terminates in acorresponding opening Duo. The bores D106 and D108 and openings Duoexist in one-to-one relationship. A plurality of internally threadedopenings D144 may be formed in the body D102 and uniformly spaced aroundeach bore opening Duo, as shown in FIG. 125, to accommodate pins D148and retainers D132 for closing the bore openings D110.

With reference to FIG. 126, each second bore D108 may have an intakeopening D118 formed proximate the bottom end of the fluid end body D102.Each intake opening D118 is connected in one-to-one relationship to acorresponding coupler or pipe. These couplers or pipes are fed from asingle common piping system (not shown).

A pair of valves D120 and D122 are positioned within each second boreD108. The valves D120, D122 route fluid flow within the body D102. Theintake valve D120 blocks fluid backflow through the intake opening D118.The discharge valve D122 regulates fluid through one or more dischargeopenings D126. A plurality of couplers D127 may be attached to eachdischarge opening D126 for connection to a piping system (not shown).

Each valve D120, D122 opens and closes due to movement of fluid withinthe internal chamber D112. A plunger D130 is provided within the firstbore D106. As the plunger D130 retracts, the discharge valve D122 closesand the intake valve D120 opens, pulling fluid into the internal chamberD112. As the plunger D130 is advanced into the first bore D106, theintake valve D120 is closed and the discharge valve D122 opens,expelling fluid from the internal chamber D112. As shown in FIG. 126,the discharge valve D122 and intake valve D120 are both closed.

A coil spring D131 is disposed on each valve D120, D122 to center thevalve and maintain its placement within the second bore D108. The coilspring D131 may also bias the valves D120, D122 in a closed position. Avalve seat D300 is provided with each valve D120, D122 such thatrepeated impacts occur between the valve and valve seat, rather than thefluid end body D102.

The valve seat D300 is disposed within the second bore D108 and seatedagainst its wall. The valve seat D300 comprises a tapered strike faceD304 (FIG. 130). The tapered strike face D304 may be hardened, orinclude a hardened insert D306 to provide durability necessary due torepeated strikes from each valve D120, D122.

With reference to FIG. 127, a prior art valve D150 is shown. Such avalve body D150 may be used as either the intake valve D120 or dischargevalve D122.

The valve D150 has a valve body D160 and an alignment structure D152 toassist in maintaining proper valve D150 orientation to the seat D300(FIG. 39) when in operation and is well known in the art. ProtrusionD154 centers the coil spring 131 (FIG. 39). When the valve D150 isclosed, a valve sealing surface D156 and valve insert D158 contact thevalve seat sealing surface (not shown) stopping fluid flow.

The valve sealing surface D156 is hardened by a post manufacturingprocess, such as nitriding or flame hardening, or is manufactured from ahard material such as carbide. It is advantageous to have the hardenedvalve sealing surface D156 to minimize erosion.

Valve insert D158 can be made of any of a number of durable elastomericmaterials well known in the art. The elastomeric material may bepolyethylene, nitryl rubber, nitrile rubber, or a similar material.Valve insert D158 may be applied to the valve body D160 and may bepermanently attached or replaceable. The purpose of valve insert D158 isto provide more sealing capability for the valve D150. While the primarysealing is accomplished by the metal to metal contact of the valvesealing surface D156 to the valve seat D300 sealing surface, it isadvantageous to have the elastomeric material encapsulate and sealaround any solids trapped between the valve insert D158 and the seatsealing surface.

Once the valve insert D158 deforms, or compresses, the valve sealingsurface D156 contacts the seat sealing surface and stops moving. Erosionoccurs with each cycle due to the impact of the valve sealing surfaceD156 on the seat sealing surface.

While the valve insert D158 does contact the seat sealing surface first,it is not designed to reduce the impact force of the valve sealingsurface D156 against the seat sealing surface, any reduction of theimpact force is incidental. The valve insert D158 instead deforms toprovide a backup, or secondary, seal for the valve sealing surface D156.In practice, the elastomeric material used for the valve insert D158retains the deformation over time and loses the ability to provide anyreduction of impact force. This loss of memory causes the valve sealingsurface D156 to apply the full force of impact on the seat sealingsurface further increasing the erosion rate until the two surfaces erodeto the point of valve D150 failure due to the lack of sealing.

With reference to FIGS. 128-130, an improved valve D200 is shown. Theimproved valve D200 may be used as either the intake valve D120 or thedischarge valve D122.

The valve D200 has alignment structure D202 to assist in maintainingproper valve D200 orientation to the seat D300, when in operation. Aprotrusion D204 disposed on the valve D200 opposite the alignmentstructure D202 to provide support for the coil spring D131 (FIG. 126).The valve D200 comprises a valve sealing surface D206 with an outerinsert D208 and an inner insert D212 disposed thereon.

When the valve D200 is closed by the spring D131, the valve sealingsurface D206, outer valve insert D208, and inner valve insert D212contact the seat sealing surface D304 stopping fluid flow.

Valve sealing surface D206 may be hardened by a post manufacturingprocess, such as nitriding or flame hardening, or is manufactured from ahard material such as carbide. It is advantageous to have the hardenedvalve sealing surface D206 to minimize erosion providing the valve D200does not fail prematurely. The area of the valve sealing surface D206 islarger than that of typical metal to metal seal valves, such as thepreviously attempted solution described above. The larger surface areais to reduce the amount of impact force per unit area imparted to thetwo sealing surfaces. If the closing force is the same and the surfacearea is increased then the amount of force per unit area is decreasedwhich reduces the amount of erosion caused by the impact force.

The outer valve insert D208 is disposed on the sealing surface D206along its outer edge, at a transition between the sealing surface D206and a side wall. Outer valve insert D208 can be made of any of a numberof elastomeric materials well known in the art. The specific material isselected based on the sealing qualities of the material in the fluidbeing controlled. Polyurethane, polyethylene, and rubber compounds maybe advantageous. As with valve D150 and insert D158, the outer valveinsert D208 provides sealing capability for the valve D200.

While the primary sealing is accomplished by the metal to metal contactof the valve sealing surface D206 to the seat sealing surface D304, itis advantageous to have the elastomeric material encapsulate and sealaround any solids trapped between the outer valve insert D208 and theseat sealing surface D304.

The inner valve insert D212 is disposed at an inner and lower extremityof the valve sealing surface D206. The inner valve insert D212 should beplaced such that its radius is approximately the inner diameter of theseat sealing surface D304. An exposed portion D207 of the valve sealingsurface D206 is disposed intermediate the inner valve insert D212 andthe outer valve insert D208. It is this exposed portion D207 thatperforms the majority of the sealing function for the valve D200.

Inner valve insert D212 can be made of elastomeric materials that aresuitable for the fluid being controlled, however the selection is basedon energy absorption capacity and memory capability of the material notthe sealing qualities. While elastomeric materials may accomplish this,a reinforced elastomer or molded urethane material may be employed insome embodiments to increase energy absorption and insert D212 life.

The two inserts D208, D212 may be made of the same material if desired.If the same material is used for both inserts D208, D212 the design maybe changed to account for the different purpose of each insert. Innervalve insert D212 will reduce the impact force between the valve sealingsurface D206 and the seat sealing surface D304. Some sealing may occurat inner valve insert D212 as well, but its primary function is that ofa shock absorber.

The sealing surface D206 fully conforms to a portion of an imaginarysmooth surface that extends between a pair of parallel planes thatrespectively limit the upper and lower ends of the valve body. Thesurface separates interior and exterior regions. The inserts D208 andD212 project within the exterior region while the sealing surface 206does not project within the exterior region.

As the valve body moves axially toward the seat during valve closure,the inserts D208 and D212 contact the seat sealing surface D304 beforethe sealing surface D206 does so. In some embodiments, the axial extentof insert D212 within the exterior region, relative to the sealing faceD206, exceeds that of insert D208. The inner insert D212 thus contactssealing surface D304 during closure of the valve before either the outerinsert D208 or valve sealing surface D206.

Any valve that uses one or more hardened surfaces may be improved byreducing the impact force of the valve sealing surface against the seatsealing surface. For instance, the inner valve insert D212 may be madeof any material that will absorb enough energy to reduce the impactforce to a level that both reduces erosion on the sealing surface D206to an acceptable rate and deforms or compresses enough to allow theexposed sealing surface D207 to contact the seat sealing surface D304.

Another embodiment may include forming the inner valve insert out ofhardened material and placing a spring or any other energy absorbingcomponent between it and the valve body, axially, to absorb the energyand allow the movement necessary to allow the hardened sealing surfacesto contact. Another embodiment may reverse the positions of the innerand outer inserts making the inner valve insert D212 the sealing insertand the outer insert D208 the energy absorption insert. Yet anotherembodiment may reverse the metal and elastomeric components with onecentral elastomeric component that is designed to absorb the necessaryenergy and the inner and outer rings being hardened metal.

Hardened sealing surfaces may be used with the reduction of failure dueto erosion. This provides for a longer service life of the valves,decreasing maintenance costs and increasing operating times.

Appendix E: Valve Having a Hardened Insert

The seat and valve geometries of FIGS. 131 and 132 may be used with thefluid end described. For the purposes of the following description ofFIGS. 131 and 132, reference numerals exclusive to those FIGS. will beused.

The valve E100 has a seal groove E104 at its radius on a sealing faceE106 of the valve E100 to allow for the insertion and retention of anelastomeric seal (not shown) as is well known in the art. While the seal(not shown) has the same material properties as those commonly used inthis industry, it differs in that it has a reduced radial dimension.Using a narrower seal and corresponding seal groove E104 providessufficient space for the carbide insert groove without having such athin wall between the two grooves E104, E108 that premature failureoccurs.

The valve E100 also has a carbide insert groove 108 on the sealing faceE106 of the valve E100. In this embodiment the carbide insert grooveE108 is at a radius smaller than that of the seal groove E104. Thecarbide insert groove E108 is sized to retain a ring-shaped carbideinsert E102. The carbide insert E102 may be retained in any number ofways known in the art. In this embodiment it is retained by aninterference fit between the carbide insert groove E108 and the carbideinsert E102.

The carbide insert E102 has a seal face E110 that is planar and flushwith the rest of the valve sealing face E106 when installed. The insertseal face E110 contacts the seal face E204 of the seat insert E202 whenthe valve E100 is closed. Since both inserts E102, E202 are hardermaterial, the erosion rate is reduced and service life increased.

Even though the service life is increased due to the presence of theharder carbide material at the sealing faces Elio, E204, the componentswill still eventually erode to the point that replacement is needed tomaintain optimal performance. It is much more difficult to replace aseat E200 than a valve E100. Therefore, valve E100 may be the componentthat wears out first. To facilitate the selective need for replacement,the carbide insert E102 in the valve E100 is purposefully selected to besofter than the carbide insert E202 of the seat E200. Even with thesofter carbide material used for the valve carbide insert E102, bothinserts E102, E202 are still much harder than their respective hostmaterial and provide a far greater life than previous valve/seatcombinations.

FIG. 132 is a cross sectional view of a valve E300. In this embodimentthe valve carbide insert E302 has a convex sealing face E306. Thisconvex sealing face E306 allows for the uneven wear or any othermisalignment between the two sealing faces E204, E306.

The elastomeric seal may be on the outside, radially, of the valve/seatassembly, but the radial positions of the elastomeric seal and carbideinsert E302 could easily be switched with appropriate modifications tothe position of the seat insert E202. Further, while the inserts aredescribed throughout this disclosure as being carbide inserts, it isalso contemplated that the insert may be made of any material that isharder than the base material of the valve. It is also contemplated thatthe convex face of the insert, as described in the second embodiment,may be any shape other than planar. Many additional non-planar shapescould provide sealing in the event of misalignment of the two sealingfaces.

Appendix F: Adjustable Valves

The valve shown in FIG. 133 is adjustable, and may be used with thefluid end described herein and the valve bodies and valve seatarchitecture previously discussed. For the purposes of the followingdescription of FIG. 133, reference numerals exclusive to it will beused.

Fluid end F100 is shown in FIG. 133. Fluid end F100 comprises a bodyF114 having an inlet port F120 and an outlet port F122 and a plungerF112. In operation the plunger F112 reciprocates in and out of the fluidend body F114 in cooperation with an inlet valve F116 and outlet valveF118 to draw fluid into the fluid end body F114 through the inlet portF120 at a lower relative pressure and expel the fluid out of the fluidend body F114 through the outlet port F122 at a higher relativepressure.

One cycle of operation for the section begins with the plunger F112 atits maximum internal position and ends when the plunger F112 returns tothat same position. The half cycle position of the plunger F112 is atthe point where the plunger F112 is at the minimum internal position.The maximum internal position generally coincides with the maximumpressure of the fluid in that section and the minimum internal positiongenerally coincides with the minimum fluid pressure in that section. Theoperating cycle of each section is offset from other sections so thatthe plunger F112 of one section is never in the same position asplungers of other sections at the same time. This is accomplished byhaving the plungers driven by a crankshaft arrangement of a power end(not shown). This offsetting of cycles is the main method used in priorart fluid end systems to control the frequency of the maximum pressurespikes and flow volume through the system.

Looking now in detail at one operating cycle for one section, FIG. 133shows the plunger F112 at the maximum inserted position. At this pointthe inlet valve F116 is in the closed position and the outlet valve F118is in the maximum open position. Fluid has been flowing out of anopening F124 between the outlet valve F118 and an outlet valve seat F126into the outlet port F122.

In the next segment of the cycle, the inlet stroke, the plunger F112recedes from the maximum inserted position to the minimum insertedposition. As the plunger F112 recedes the volume of a pressure chamberF132 increases thereby reducing the pressure in the pressure chamberF132. In prior art fluid ends, this change in pressure causes the outletvalve F118 to close and the inlet valve F116 to open to the maximum openposition.

The third segment of the cycle is the minimum inserted plunger F112position. At this point the outlet valve F118 is in the closed positionand the inlet valve F116 is in the fully open position. Pressure in thepressure chamber F132 will be at a minimum and the pressure chamber F132volume will be a maximum.

The fourth segment of the cycle is the pressure stroke. The plunger F112advances to the maximum inserted position. As the plunger F112 advancesthe volume of the pressure chamber F132 decreases thereby increasing thepressure in the pressure chamber F132.

In prior art fluid end designs, the travel and positions of the inletand outlet valves are determined passively by the spring rates of valvesprings and placement of stops to limit the travel of the valves. In theembodiment of FIG. 46, however, the positions of the inlet valve F116and outlet valve F118 are determined from the measurement of systemparameters and by positive placement of each valve by a hydrauliccylinder F102 in cooperation with a push rod F104. While the push rodF104 is moved by a hydraulic cylinder F102 in the embodiments listed anytype of device that can positively position the push rod F104 and or thevalves F116, F118 is contemplated. For instance, the cylinders F102could operate on pressurized air, or be electric motors.

In operation there are numerous sensors measuring system parameters andproviding input to a processor or multiple processors to determine theoptimum position of each valve F116, F118 at any given time. Theprocessor then controls each hydraulic cylinder F102, specifically theflow into and out of each hydraulic cylinder F102, to place the valvesF116, F118 at the previously determined optimum position. As the needsof the operator change the system parameters can be changed in thecontrol system allowing each valve F116, F118 to be placed in adifferent position at a different time in the operating cycle thanpreviously without having to change any components of the system exceptfor the computer code operating the control system.

As an example, position sensors may be placed to determine the positionof the valves F116, F118 attached to each cylinder F102. A positionsensor may also be placed to determine the position of the plunger F112.The exact type and positioning of these sensors is not important forthis example only that they accurately provide the position of thevalves F116, F118 and the plungers F112 for every section at any pointin the cycle. These position sensors may be any of those well known inthe art, for example linear variable displacement transducers (LVDT).

There may also be pressure sensors placed in the pressure chambers F132of each section, the inlet port F120 and outlet port F122 of eachsection, an upstream position prior to separation into individual inletsections and a downstream position after the combination of each outletflows into a common outlet conduit. There may also be pressure sensorsplaced in the hydraulic system. There may also be flow meters at variouspoints in the system to provide information to the control system. Anysystem measurement used to determine valve F116, F118 or plunger F112positioning, or fluid state may be used. The system measurements willcooperate to provide information to the control system which in turnprovides input to each hydraulic cylinder F102 for the desiredpositioning of the inlet valve F116 and outlet valve F118.

In operation, a desired outlet fluid profile is determined. This desiredoutlet fluid profile can be described by parameters such as fluidpressure, flow rate, temperature, viscosity, velocity, or any otherfluid flow parameters deemed important to the operator and measurable bythe system sensors, or at least capable of being input to the controlsystem.

Once the desired output fluid profile is entered into the control systemoperation begins. The system sensors provide input to the control systemwhich then control the hydraulic pump or pumps and valves which in turnsend the appropriate amount of hydraulic fluid to the correct hydraulicport F106 of the hydraulic cylinders F102 to place the valves F116,F118, at a desired velocity, in a desired position at a desired time.The exact position of the valves F116, F118 may be determined by thelength of the push rod F104 and position of the hydraulic cylinderpiston F108, or by direct measurement, or by inference from the pressureof the hydraulic fluid in either or both sides of the hydraulic cylinderF102 or any other method that provides the control system with theactual position of the valves F116, F118.

The adjustment of the amount of valve opening, the velocity at which thevalve F116, F118 travels to the position, and the time at which thevalve F116, F118 gets to a position and how long it stays at theposition all affect the fluid profile. As an example, if the outletvalve F118 is held closed until the plunger F112 reaches the maximuminternal position then opened at a high velocity to a relatively largeamount of opening then the outlet pressure and flow would spike.Conversely if the outlet valve F118 is opened to the same position at arelatively low velocity as the plunger F112 approaches maximum internalposition the pressure and flow will not spike as much. Numerouscombinations of plunger F112 position and velocity, valve F116, F118position, valve F116, F118 opening and closing velocity, and the timethe valve F116, F118 spends at any position also known as dwell time canmanipulate the outlet and inlet fluid profiles.

The measured outlet fluid profile is compared to the desired outletfluid profile and if needed control system parameters are adjusted basedon known effects of each system parameter on the outlet fluid profile toadjust the measured outlet fluid profile to match the desired outputfluid profile. The process is repeated until the job is completed oruntil a different desired outlet fluid profile is input to the system.

The desired inlet fluid profile may be input to the control system inaddition the desired outlet fluid profile. In operation the measuredoutlet and inlet fluid profiles would be compared to the desiredprofiles and if needed control system parameters adjusted based on knowneffects of each system parameter on the outlet and inlet fluid profilesto match the measured profiles to the desired profiles.

In operation the relative positions, and the velocity at which thosepositions are reached, of each pertinent component is predetermined andmaintained using the control system. For example, an operator may desireto minimize erosion of valve faces F134, F146 and valve seat faces F148,F150 due to the high impact forces normally associated with conventionalspring return valves. Using the present system, the operator may programthe control system to open and close the valves F116, F118 at apredetermined velocity. The operator may also program the control systemto move the valves F116, F118 at a higher velocity until just before thevalve faces F134, F146 contact the valve seat faces F148, F150 thusreducing the impact velocity and resultant erosion.

Alternatively, the goal may be to provide as much clearance as possiblebetween the valve faces F134, F146 and the valve seat faces F148, F150.This could occur if a high-volume proppant is to be pumped into aformation as in the hydraulic fracturing process. The ability to adjustthe amount of opening between the valve faces F134, F146 and the valveseat faces F148, F150 will reduce the erosion damage to each face F134,F146, F148, F150 due to the proppant.

A means for independently controlling the position of the plungers F112may be used. This may or may not be used in cooperation with theindependent control of the positions of the valves F116, F118. Toindependently control the plungers F112 an independent drive source issupplied to each plunger F112. The position of the plungers F112 to eachother is not fixed as it is when they are driven by a crankshaft as iscommon in power ends. The independent drive source for each plunger F112is controlled by the control system in cooperation with the measurementsystem.

The fluid end is now described in more detail, utilizing the discussiongiven with reference to FIGS. 80-94, and those reference numbers.

Continuing with FIGS. 80 and 82, the fluid end 100 further comprises aplurality of sets of components A128 and A130. The number of sets equalsthe number of sets of paired first and second bores A106 and A108 formedin the body A102. The component A128 is positioned within a first boreA106, and the component A130 is positioned within its paired second boreA108. In one embodiment, the component A128 is a suction plug and thecomponent A130 is a discharge plug. Each of the components A128 and A130are substantially identical in shape and construction, and each is sizedto fully block fluid flow within the respective bore A106, A108. A sealA136 is positioned around the outer surface of each component A128, A130to block fluid from leaking from the bores A106, A108.

Appendix G: Sealing Locations within Fluid Ends

Sealing locations discussed in FIGS. 134-141 may be used with the fluidend described herein and the valve bodies and valve seat architecturepreviously discussed. For the purposes of the following description ofFIGS. 134-141, reference numerals exclusive to those FIGS. will be used.

FIG. 134 is a simplified isometric cross-sectional depiction of ahydraulic fracturing fluid end G200 that is constructed in accordancewith previously attempted solutions. The fluid end G200 is generally amanifold G201 used to deliver highly-pressurized corrosive and/orabrasive fluids, typically used in hydraulic fracturing processes in theoil and gas industry. Fluid may pass through the fluid end 200 atpressures that range from 5,000-15,000 pounds per square inch (psi).Fluid ends G200 used in high pressure hydraulic fracturing operationstypically move fluid at a minimum of 8,000 psi. However, normally, thefluid end G200 will move fluid at pressures around 10,000-15,000 psi.

The manifold body or housing G201 typically has a first conduit G220 anda second conduit G221 formed within the body G201 that intersect to forman internal chamber G222. The first conduit G220 is typically orthogonalto the second conduit G221. The first conduit G220 may have alignedfirst and second sections G223 and G224 that are situated on oppositesides of the internal chamber G222. Likewise, the second conduit G221may have aligned third and fourth sections G225 and G226 that aresituated on opposite sides of the internal chamber G222. The sectionsG223, G224, G225, and G226 each may independently interconnect theinternal chamber G222 to an external surface G227 of the fluid end G200.

A plunger G228 reciprocates within the body G201 to increase thepressure of fluid being discharged from the fluid end G200. As shown inFIG. 134, the plunger G228 may be disposed within the third section G225of the second conduit G221. The plunger G228 is powered by an engineoperatively engaged with the fluid end G200. In high pressure hydraulicfracturing operations, the engine may have a power output of at least2,250 horsepower. Valve seats G229 are also shown within the firstconduit G220. The valve seats G229 may support valves, such as a ballvalve, used to control the movement of high pressure fluid within thebody G201.

The body G201 defines a discharge opening G202 that opens into the firstconduit G220. The discharge opening G202 depicted in these embodimentsis sealed closed by inserting a closure or discharge plug or cover G204into the conduit G220 and securing it by advancing a retaining nut G206into the body G201. The discharge plug G204 supports a seal G208 thatseals against the bore defining the discharge opening G202. FIG. 48 is asimplified cross-sectional depiction of the discharge plug G204 that hasa surface G205 defining a recess G207 into which the seal G208 ismounted at an inner radial surface G211 of the radial seal G208.

In these illustrative embodiments the recess G207 is rectangular but thecontemplated embodiments are not so limited. The skilled artisanunderstands that the configuration of the recess G207 is largelydetermined by what shape is required to mount the type of seal selected.The recess G207 intersects an outer surface G215 of the discharge plugG204, permitting the seal G208 to be sized so that a portion not mountedwithin the recess G207 extends beyond the outer surface G215 topressingly engage against the bore G209 defining the discharge openingG202. In this construction the highly-pressurized corrosive and/orabrasive fluid can harsh fluid can be injected between the seal G208 andthe bore G209, causing erosion of the seal surface formed by the boreG209. This technology transfers that erosion wear from the body boreG209 to the less complex and less expensive discharge plug G204.

Fluid end bodies have conventionally been made of heat-treated carbonsteel, so it was not uncommon for the body G201 to crack before anysacrificial erosion of the body progressed to the point of creatingleakage between the discharge plug G204 and the bore G209. However,progress in the technology has introduced stainless steel bodyconstruction resulting in a significantly longer operating life. As aresult, this erosion is no longer negligible but is instead aconsideration for reducing erosion in modern fluid end construction. Oneleading source of bore G209 erosion in conventional fluid ends is theseal G208 mounted in the discharge plug G204 and extending therefrom toseal against a sealing surface formed by the body G201.

FIG. 136 is an exploded cross-sectional depiction of a fluid end G230that is constructed in accordance with this technology to, in numerousplaces, transfer the erosion wear from the body to the less complex andless expensive component that is sealed to the body. A manifold bodyG232 forms a number of interconnected bores or conduits, including afirst conduit or discharge bore G234 forming a discharge opening G235that is similar to the discharge opening G202 in the conventional fluidend G200 depicted in FIG. 134. The discharge bore G234 further definesan intake opening G231 formed opposite the discharge opening G235. Theterm “discharge bore” for purposes of this description means the surfacedefining the discharge opening G235 into which a closure or dischargeplug G236 and a retaining nut G238 are installed, and the surfacedefining the intake opening G231. For clarity, although FIG. 49references the discharge bore G234 as defining an upper end of thedischarge opening G235 where the retaining nut G238 attaches, thedischarge bore G234 also references lower portions of the dischargeopening G235 where the discharge plug G236 seals to the body G232 andwhere the valve seat (not depicted) seals to the body G232. Likewise,the discharge bore G234 also references upper portions of the intakeopening G231. Generally, for purposes of this description the dischargebore G234 forms multi-dimensional diameters at different longitudinallocations of the discharge opening G235 and intake opening G231.

The discharge opening G235 is sealed closed by inserting the dischargeplug G236 into the discharge opening G235 and securing it in place byadvancing the retaining nut G238. Unlike the conventional plug G204 inFIG. 48, however, the plug G236 does not have a seal mounted to it thatseals against the bore G234. Instead, the plug G236 defines a sealingsurface 237 for a seal (not depicted in FIG. 136) that is mounted in anendless groove or recess formed by a surface G239 of the body G232. Thesealing surface G237 is axially spaced between a first surface G251 andan opposite second surface G253 of the plug G236.

FIG. 137 is a simplified cross-sectional enlargement depicting theconstruction of the seal positioned within the surface G239 of the bodyG232. The surface G239 forms an endless groove or recess G240 thatintersects the discharge bore G234. A seal G242 in these illustrativeembodiments is mounted in the recess G240 to include an outer radialsurface, and is thereby supported by the body G232. The recess G240 ischaracterized by a pair of parallel sidewalls joined by a base. Therecess G240 opens towards a centerline of the conduit within which it isformed. Alternatively, as shown by recess G266 in FIGS. 139-140, therecess may open in a direction parallel to a centerline of the conduitwithin which it is formed. As above, the rectangular-groove shape of therecess G240 is merely illustrative and not limiting of the contemplatedembodiments. Any shape necessary to properly mount a desired seal iscontemplated, whether the seal is elastomeric, spring, metal, and thelike. As above, the recess G240 intersects the bore G234 permitting theseal G242 to be sized so that a portion of the seal G242 not containedin the recess G240 extends beyond the recess G240 and beyond the boreG234 to pressingly seal against the sealing surface G237 (FIG. 136)defined by the discharge plug G236.

This seal construction depicted in FIG. 137 transfers the erosion wearfrom the body to the discharge plug. That significantly improves fluidend operations because repairs involving the discharge plug G236 aresignificantly less complex and less expensive than repairs involving thebody G232, which typically involve weld-repair. Furthermore,weld-repairing the body G232 makes it susceptible to premature fatiguecracking in the repaired area. Further, even more operating life can beachieved by applying an erosion-resistant surface treatment to the plugG236, such as a high velocity oxygen fuel (HVOF) treatment, a tungstencarbide coating, material carburizing, and the like. Replacing insteadof repairing an eroded discharge plug G236 is typically feasible, makingit advantageously possible to repair a leaking valve constructedaccording to this technology in the field and thereby significantlyreducing down time.

Returning to FIG. 136, the body G232 has a surface G241 defining anendless groove or recess intersecting the bore G234 and configured tomount a seal (not depicted) that extends from the recess to seal againsta sealing surface formed by a discharge valve seat (not depicted).Similarly, the body G232 has a surface G243 forming another endlessgroove or recess intersecting the bore G234 and configured to mountanother seal (not depicted) that is sized to extend from the recess toseal against a sealing surface formed by a suction valve seat (notdepicted). The multiple references to a same bore G234 is for purposesof ease of description and is not narrowing of the contemplatedembodiments of this technology. Whether the recesses defined by surfacesG241, G243 are formed in the same bore or different bores does not alterthe scope of the contemplated embodiments directed to the recess formounting the seal is formed in the body, and a seal is mounted in therecess and from there seals against a sealing surface of a component ina sealing engagement therebetween.

Similarly, a suction bore G247 is sealed closed by inserting a closureor suction plug or cover G244 defining a sealing surface G245 andsecuring it in place by advancing a retaining nut G246 in the body G232.Like the plug G236, the sealing surface G245 is axially spaced between afirst surface G255 and an opposite second surface G261 of the plug G244.Again, the body G232 in these illustrative embodiments has a surfaceG248 forming an endless groove or recess intersecting the bore G247 andconfigured for mounting a seal (not depicted) extending from the recessand sealing against the sealing surface G245 of the suction plug G244.That transfers the wear from the body G232 to the suction plug G244 incomparison to previously attempted solutions and in accordance with theembodiments of this technology.

The body G232 also forms a plunger opening G250 sized to closely receivea stuffing box sleeve G254 that is sealed in place by advancing aretaining nut G256. The stuffing box sleeve G254 is characterized by atubular sleeve. The plunger G228, shown in FIG. 136, may be disposedwithin the stuffing box sleeve G254.

The opening G250 is formed in part by the plunger bore G252 having asurface G257 defining an endless groove or recess intersecting the boreG252, into which a seal (not depicted) is mounted in these illustrativeembodiments. The suction bore G247 and the plunger bore G252 togetherform the second conduit. Although these illustrative embodiments use aradial seal, the contemplated embodiments are not so limited. Inalternative embodiments other types of constructions are contemplated bythis technology employing axial seals, crush seals, and the like.

FIG. 138 is a simplified cross-sectional depiction of the body G232having the surface G257 forming the recess G258. Again, the recess G258intersects the body bore G252 permitting a portion including an outerradial surface of a radial seal G260 to be mounted in the recess G258.Another portion of the seal G260 not mounted in the recess G258 extendsfrom the recess G258 to pressingly seal against the sealing surface G259of the sleeve G254. Although in these depicted embodiments a radial sealis used, the contemplated embodiments are not so limited. The skilledartisan readily understands that other types of seals could be usedinstead of or in addition to the radial seal depicted, such as axialseals, crush seals, and the like.

FIG. 139 depicts a number of additional endless grooves or recesses inthe body G232 for mounting various seals to transfer the wear away fromthe body G232 to the mating component in accordance with embodiments ofthis technology. For example, the body G232 has a surface 266 defining arecess G273 intersecting the body bore that defines the dischargeopening G235. Consistent with this whole description, this permitsmounting an axial seal G268 (not depicted in FIG. 139, see FIG. 140) inthe recess G273, the seal G268 configured to extend from the recess G273to seal against a leading face of the discharge plug G236 (FIG. 136).FIG. 140 is a simplified enlarged depiction of the body G232 having asurface G266 defining the recess G273 into which an axial seal G268 ismounted. In these illustrative embodiments the seal G268 is configuredto extend beyond the body bore defining the discharge opening G235 toseal against the discharge plug G236 as it is urged downward byadvancing the retaining nut G238 (FIG. 136).

Importantly, the simplified seal construction depicted in FIG. 140 andelsewhere is in no way limiting of the contemplated embodiments andscope of the claimed technology. In alternative embodiments a radialseal or a crush seal and the like can be employed to transfer theerosion wear from the body G232 to the mating component. A crush sealrefers to a seal construction that acts at least to some degree bothaxially and radially. For example, surface G272, shown in FIG. 139,forms a recessed corner having two walls that extend concentricallyaround the bore G252 (FIG. 136). The stuffing box sleeve G254 may beformed to have side walls that fully overlie the corner section formedby surface G272 when it is positioned in the bore G252. This allows theseal to act as a crush seal because it seals axially and radiallyagainst the sleeve G254.

Returning to FIG. 139, the body G232 can have other surfaces formingendless grooves or recesses for mounting various other seals. Forexample, surface G270 forms a recess for mounting a seal that isconfigured to seal against a sealing surface of a suction plug (notdepicted), like in FIG. 140. In the same way the body G232 can havesurfaces G272, G274, G276 forming recesses for mounting seals that areconfigured to seal against sealing surfaces of the stuffing box sleeveG254 (FIG. 136), the discharge valve seat (not depicted), and thesuction valve seat (not depicted), respectively. Likewise, the body G232can have a surface G278 forming a recess for mounting a seal that isconfigured to seal against a suction manifold (not depicted). What'scommon in any event is the seal construction of this technologytransfers the seal wear from the body G232 to the less complex and lessexpensive mating component that is attached to the body G232.

FIG. 141 depicts the stuffing box sleeve G254 (FIG. 136) inserted intothe plunger opening G250 so that a seal G260 mounted in the recess G258formed by the surface G257 extends from that recess G258 and sealsagainst the sealing surface G259 defined by the stuffing box sleeveG254. As the stuffing box sleeve G254 is inserted into this position airpressure forms in a space defined in the clearance gap between the outerdiameter of the stuffing box sleeve G254 and the body bore defining theplunger opening G250 and between the seal G260 and a seal G286 at anopposing end of the stuffing box sleeve G254. The air pressure exerts aforce urging the stuffing box sleeve G254 out of the plunger openingG250, complicating manufacture and degrading the seal integrity at thelower end of the stuffing box sleeve G254. A breather opening G284 canbe formed between that space and ambient space above the stuffing boxsleeve G254 to vent the air pressure.

FIG. 141 also depicts a conventional construction of the seal G286 thatis mounted in a recess formed by the stuffing box sleeve G254 andextends from that recess to seal against the body bore defining theplunger opening G250. The contemplated embodiments can includecombinations of the conventional construction and the construction ofthis technology where other matters come into play. For example, withoutlimitation, it can be feasible to use a stuffing box sleeve G254depicted in FIG. 141 if it can be manufactured or otherwise acquiredless expensively than providing the recess instead in the body G232, andif the particular seal location is one that is not necessarily criticalin its role for the overall design for maintaining thehighly-pressurized fluid in the flow passage.

FIG. 141 also depicts employing the open-cylinder-shaped stuffing boxsleeve G254 and securing it in place by advancing the retaining nut G256(FIG. 136). That construction is illustrative and in no way limiting ofthe contemplated technology. Other configurations can be employed aswell. For example, the skilled artisan understands that a conventionalstuffing box can be employed that combines the stuffing box sleeve G254and the retaining nut G256, unitarily, into one component that has arecess for supporting a seal configured to seal against the body boredefining the plunger opening G235. In other conventional constructions astuffing box without that recess is used in combination with a sealcarrier insert that mates with the stuffing box and provides the recessfor mounting the seal. In yet other contemplated embodiments thestuffing box sleeve G254 can be modified to a construction combining asubstantially cylindrical-shaped stuffing box to which is mated a sealsurface insert that provides the sealing surface G259 (FIG. 136).

In FIG. 136, the sleeve G254 also protects the bore G252 from erosion byproviding an inner diameter surface G264 against which the stuffing boxpacking (not depicted) seals. That, again, by design transfers the wearfrom the body G232 to the less complex and less expensive sleeve G254.

Summarizing, this technology contemplates a high pressure fluid flowapparatus constructed of a body defining a flow passage, a closuremounted to the body, and a means for sealing between the body and theclosure. For purposes of this description and meaning of the claims theterm “closure” means a component that is attached or otherwise joined tothe body to provide a high-pressure fluid seal between the body and theclosure.

Appendix H: Bellows System

The bellows system described in FIGS. 142-148 may be used with the fluidend previously described and in combination with all its components. Forthe purposes of the following description of FIGS. 142-148, referencenumerals exclusive to those Figures will be used.

One drawback of conventional systems is that seals must be used toprevent leakage around the reciprocating plunger. Specifically, sealsmust be installed on the internal surface of the retainer nut, throughwhich the plunger extends. Fracturing fluid is abrasive, and such fluidat high pressure may cause wear on the reciprocating plunger and damageto the seals over time. Therefore, it would be advantageous to limit theexposure of dynamic seals to the high pressure, abrasive fracturingfluid.

Turning to FIGS. 142-148, a fluid end H10 is shown. The fluid end has amanifold body or housing H11. The housing may be formed in one piece, ormay be formed of multiple sections, such as sections H11 a and H11 bshown in FIGS. 142-145. When a multi-piece body H11 is used,through-holes H13 allow for connectors (not shown), such as bolts, toconnect sections H11 a, H11 b.

The housing H11 typically has a first conduit H20 and a second conduitH21 formed within the body H11 that intersect to form an internalworking chamber H22. The first conduit H20 is typically orthogonal tothe second conduit H21. The first conduit H20 may have aligned first andsecond sections H23 and H24 that are situated on opposite sides of theinternal chamber H22. The second conduit H21 may also be referred toherein as a plunger bore.

The conduits H20, H21 each may independently interconnect the internalchamber H22 to an external surface H27 of the fluid end H10. Fluidtravels into the chamber H22 through an inlet opening H40 when an inletvalve H42 is open. Fluid travels out of the chamber H22 to a dischargeopening H44 when a discharge valve H46 is open. A plunger H28 having asmooth external surface reciprocates within the plunger bore H21 tochange the effective volume of the internal chamber H22. As shown, theplunger H28 is disposed in a bellows H100 seated within the plunger boreH21. The plunger H28 is driven by a power end (not shown) and powered byan engine.

As shown in FIGS. 142-144, fluid end H10 typically comprises three tofive plungers H28 and an equal number of working chambers H22. In FIG.142, a five-plunger, or quintiplex, fluid end H10 is shown. It should beunderstood that a bellows may be utilized in one, many, or all of thesections of a fluid end H10.

The first section H23 is a conduit that allows fluid to enter the bodyH11 at intake opening H40, and thereafter to move into the internalchamber. A one-way suction valve H42 is positioned within the firstsection H23, and prevents backflow in the direction of the intakeopening H40.

The second section H24 is a conduit that allows fluid to exit theinternal chamber H22, and thereafter leave the body H11 through thedischarge opening H44. A one-way discharge valve H46 is positionedwithin the second section H24, and prevents backflow in the direction ofthe chamber H22.

A valve seat H29 is formed in each of the first and second sections H23and H24. Each valve seat H29 is shaped to conform to a surface of thevalve that is received within the same section. Thus, the valve seat H29within the first section H23 conforms to a surface of the suction valveH42. Likewise, the valve seat H29 within the second section conforms toa surface of the discharge valve H46. The valves H42, H46 close againstthe removable valve seats H29 rather than against a surface of themanifold body H11. As wear due to valve closure occurs, that wear isfocused primarily at the seats H29, rather than at the body H11.Replacement of worn seats is far less costly than replacement of a wornbody H11. A spring H47 is received within each of the sections H23 andH24. Each spring engages the valve received within the same section, andbiases that valve towards its seat.

Each plunger H28 may reciprocate out of phase with the other plungers.This phase relationship allows the fluid end H10 to maintain pressurewithin the body at an approximately constant level. Fluid outputdownstream from the body H11 is kept approximately constant as a result.

The fluid end H10 further comprises a bellows H100 and an annularretainer nut H102. The annular retainer nut H102 defines acentrally-disposed passage H104 therethrough. The plunger H28 extendsthrough the passage H104 of the retainer nut H102 and into the bellowsH100. Several kits are useful for assembling a fluid end H10. A firstkit comprises the bellows H100, retainer nut H102, and plunger H28 forplacement within the plunger bore H21 of a fluid end H10, as shown inFIG. 144. A second kit comprises the same bellows H100, retainer nutH102, and plunger H28 for placement in a second plunger bore. Third,fourth and fifth kits may be used as well. Additional components of thefluid end H10 may be added to any of these kits.

The bellows H100 is formed from a strong, durable and metallic material,and includes alternating folds or pleats H105. The bellows H100 may bemade entirely of high-strength material, such as steel, or may be acomposite of more than one such material. The pleats H105 permit thebellows H100 to move between retracted and extended positions. Thebellows H100 has an exterior and interior. The exterior is exposed tothe fluid and pressure of the internal chamber H22 and plunger bore H21of the fluid end H10. The interior forms an internal cavity H106 that isisolated from the internal chamber H22 and plunger bore H21 by thebellows H100.

The portion of the plunger H28 extends through the passage H104 of theretainer nut H102 so that its end is disposed within the cavity H106.When in operation, the plunger H28 is at least partially surrounded bythe bellows H100.

The cavity H106 is in fluid communication with a fluid passage H107disposed in the annular retainer nut H102. The cavity H106 is filledwith a fluid. The fluid may be incompressible fluid, such as water,hydraulic oil, motor oil, or mineral oil. By “incompressible”, what ismeant is a fluid with a very low compressibility. Such fluid is pumpedvia the fluid passage H107 into the cavity H106. Once filled, the cavityand fluid passage are sealed.

The volume of the fluid within the cavity is static. When the plungerH28 presses against the bellows H100, the cavity H106 deforms, and thefluid it contains is displaced. Such fluid displacement causes thebellows H100 to extend. As the plunger H28 retracts from the cavity,fluid fills the void left by the plunger, causing the bellows H100 toretract. Therefore, the cavity H106 displaces as shown by the differencebetween FIG. 146 and FIG. 147. The displacement of the cavity H106 isproportional to the additional plunger H28 volume disposed within thecavity.

The bellows H100 is positioned within the plunger bore H21, and securedat its first end H108 to the body H11. As shown, a stuffing sleeve H110is disposed inside the plunger bore H21. The stuffing sleeve H110surrounds the bellows adjacent its first end. This sleeve H110 is sealedagainst the body H11 at a radial seal H11. The sleeve H110 abuts theannular retainer nut H102. In one embodiment, the first end H108 may beattached to the body H11 adjacent the stuffing sleeve H110. As shown,the bellows H100 at its first end H108 is sandwiched between theretainer nut H102 and a shoulder formed in the stuffing sleeve H110.

A second end H109 of the bellows H100 extends within the plunger boreH21 towards the working chamber H22. The second end H109 may be circularto match the sectional shape of the plunger bore H21. As shown in FIG.148, each of the plunger bore H21, stuffing sleeve H110, bellows H100,and plunger H28 have a circular cross-section.

The bellows H100 is not to scale in the Figures. The wall forming thepleats H105 of the bellows boo may in fact be much thinner than shown inthe Figures. In one embodiment, the bellows H100 may have a thickness ofa tenth of an inch or less along its wall.

In operation, as the plunger H28 is pushed into the cavity H106, thepleats H105 unfold, causing the bellows H100 to accordion into itsextended position. The second end H109 of the bellows H100 displacesfluid within the working chamber H22, forcing the fluid past thedischarge valve H46 and out of the discharge opening H44. The bellowsH100 is shown in its extended position in FIG. 147.

As the plunger H28 is retracted from the cavity H106, the pleats H105fold and the bellows H100 accordions into a retracted position. As thesecond end H109 of the bellows withdraws from the working chamber H22,the discharge valve H46 closes and the suction valve H42 opens. Fluid ispulled into the working chamber H22 through the intake opening H40. Thebellows H100 is shown in its retracted position in FIG. 146.

The cavity H106 should be maintained at approximately the same pressureas the working chamber H22. Such pressure equalization protects thestructural integrity of the bellows H100. Too low a pressure in thecavity H106 may cause the bellows H100 to collapse, while too high apressure in the cavity may cause the bellows H100 to balloon outward.

The fluid is provided at low pressure, or vacuum pressure, when thefluid end H10 is not in operation. When the fluid end H10 operates, thepressure within the working chamber H22 is transferred directly to thebellows H100. The bellows then exerts a force on the fluid within thecavity H106. This causes the pressure differential to be minimal betweenthe chamber H22 and the cavity H106. In some embodiments, this pressuredifferential is less than 500 psi.

The fluid end further comprises a clean-out section H48 that may beclosed by a removable retainer nut H50. Components of the fluid end H10,such as the valve seats H29, valves H42, H46, and various seals may beserviced or replaced through the clean-out section H48.

The second section H24 is likewise enclosed by a retainer nut H50. Eachretainer nut H50 and annular retainer nut H102 may be attached to thefluid end body H11 by bolts H52 extending into the body H11. In the nutH102, opening spaced peripherally about the central opening H104 receivethe bolts H52. Such an arrangement may allow the nut H102 to be affixedto the body H11 without internal threads within the plunger bore H21.

Another embodiment, not shown in the figures, does not include any boltsH52. Instead, external threads are provided on each of the retainer nutsH52 and H102. These external threads mate with internal threads formedwithin the conduit into which the retainer nut is installed.Specifically, internal threads may be formed on each of the clean outsection H48, first section H23, second section H24, and plunger boreH21.

The annular retainer nut H102 defines one or more grooves H130 formed inthe central passage H104. These annular grooves H130 each contain aradial seal H132. The radial seals H132 prevent leakage of fluid fromthe cavity H106 as the plunger H28 reciprocates. To minimize the risk ofleakage, multiple seals at the central passage H104 is may be employed.

The seals H132 are the only seals in the plunger bore which seal againsta moving surface. As discussed above, the fluid in the cavity H106 maybe a hydraulic oil or motor oil. As this fluid is not abrasive, theseals H132 that protect cavity H106 experience relatively low levels ofwear. In contrast, in a conventional fluid end, the seals that bearagainst moving surfaces are exposed to the abrasive fluids that movethrough the chamber H22. These seals experience much greater levels ofwear.

Appendix I: Plug Configured to Provide Bore Clearance

Plugs discussed in FIGS. 149-152 may be used with the fluid enddescribed herein and the valve bodies and valve seat architecturepreviously discussed. For the purposes of the following description ofFIGS. 149-152, reference numerals exclusive to those Figures will beused.

FIGS. 149-152 show a suction plug I100, FIG. 149, and a discharge plugI102, FIG. 150. FIGS. 151-152 show the plugs I100, 102 assembled in afluid end body 104 as they are during operation. Note the sealingsurfaces I106 of the joints are on the respective plugs I100, I102 whilethe seals I108 are mounted in grooves I110 in the fluid to end bodyI104.

The wear surface of the seal joint between the plugs and the body I104is on the plugs I100, I102. The plugs I100, I102 can be replaced easierand with less expense than repairing the fluid end body. This does notrequire the seals I108 to be mounted in the fluid end body I104.

FIG. 62 shows a suction plug I100 with a generally cylindrical shapehaving a cylindrical axis I112. The suction plug Iwo has a mountingflange I114 with mounting holes I116 through which bolts (not shown) areassembled to retain the suction plug I100 in its correct position in thefluid end body I104 during operation. The diameter of the portion of thesuction plug I100 that is inserted into the fluid end body I104 to sealthe suction bore I118 is generally smaller than the diameter of themounting flange I114 and in this embodiment has multiple sections alongthe cylindrical axis I112 of the suction plug too with differentdiameters.

The sealing surface I106 of the suction plug I100 is the portion of thesuction plug boo inserted in the fluid end body I104 with the maximumoutside diameter and is positioned opposite the seal I108 duringoperation as shown in FIG. 151. For proper sealing the diameter of thesealing surface I106 may be sized to have an interference fit with theinside diameter of the seal I108. This sizing also results in thesmallest clearance between the outside diameter of the suction plug Iwoand the inside diameter of the suction bore I118 of the fluid end bodyI104. This small clearance increases friction during assembly anddisassembly. To minimize this friction the shortest axial segmentpossible is sized to the diameter needed for sealing. This shortestpossible segment is the sealing surface I106 of the suction plug I100.The sections I120, I122 on either side, axially, of the sealing surfaceI106 have reduced diameters. The section I120 of the suction plug 100the farthest distance away from the mounting flange I114, axially, mayalso have a chamfered nose I124 to assist in the initial alignment ofthe suction plug I100 as it is inserted in the suction bore I118 andseal I108.

To assemble, the suction plug I100 is inserted in the suction bore I118and an axial force is applied to the outside surface I126 sliding thesealing surface I106 and adjacent sections I120, I122 into the suctionbore I118 along the cylindrical axis I112. Once the suction plug I100 isinserted far enough into the suction bore I118 the retention bolts areinserted through the mounting holes I116 of the mounting flange I114 andtightened into threaded holes (not shown) of the fluid end body I104.When the retention bolts are tightened to the appropriate torque thesealing surface I106 of the suction plug I100 is positioned to sealagainst the seal I108 installed in the fluid end body I104. Since theaxial length of the sealing surface I106 has been minimized the axialforce required to insert the suction plug I100 to the correct positionin the fluid end body I104 has been reduced from that required to inserta plug with its entire inserted axial length the same diameter as thatrequired for the sealing surface.

Another advantage of the smaller diameter sections I120, I122 before andafter, axially, the larger diameter section of the sealing surface I106is the diametrical clearance provided by the smaller diameter sectionsI120, I122 that allows the suction plug I100 to be rotated about an axisperpendicular I128 to the cylindrical axis I112 of the suction plugI100. This allows the suction plug I100 to be “rocked up and down” asthe insertion force is being applied. The sealing surface I106 is thefulcrum for the perpendicular axis I128 rotation which allows thesuction plug Iwo to be worked in step wise. The suction plug I100 isrotated about the perpendicular axis I128 from the position where afirst contact point I130 on the outside diameter of the smaller diametersection I122 closest to the mounting flange I114 contacts the innerdiameter of the suction bore I118 while a second contact point I132diametrically opposite the first contact point I130 and on the smallerdiameter section I120 farthest from the mounting flange I114, contacts apoint on the inside diameter of the suction bore I118.

To disassemble, a threaded rod (not shown) is torqued into a threadedhole I134 in the outside surface I126 of the suction plug I100. Thethreaded hole I134 may be coincident with the cylindrical axis I112. Thethreaded rod may be a component of a slide hammer. A force is applied tothe threaded rod to remove the suction plug I100 from the suction boreI118. The force may be generally along the cylindrical axis I112. Thediametral clearance provided by the smaller diameter sections I120, I122also allows the suction plug Iwo to be rotated about the perpendicularaxis I128 while the removal force is being applied along the cylindricalaxis I112. This rotation allows the suction plug I100 to be worked outof the suction bore I118 in a step wise fashion using the sealingsurface I106 as a fulcrum as described above. However, in this instancethe suction plug I100 is being removed instead of inserted. The basicstructure, assembly, and disassembly are the same for the discharge plugI102 and discharge bore I136.

Alternatively, material may be removed from the bores to provide thediametral clearances needed to allow the rotation of the plugs about theaxis perpendicular to the cylindrical axis. In this embodiment thediameter of the bores are increased before and after the seals which hassegment with an axial length of a smaller diameter to support the seals.The diameter of the plugs may be constant in this embodiment. Oneskilled in the art can appreciate the possibility of using anycombination of reduced outside diameter of the plugs combined with anincreased diameter of the bores to allow the rotation of the plugs aboutthe perpendicular axis or possibly both increasing the diameter of thebores and decreasing the diameter of the plugs in areas that are not thesealing surface or supporting the seal. The fulcrum, or center ofrotation would always be the sealing area of the plug and bore.

The diameter of the plugs may be reduced on only one side of the sealingsurface. This would reduce the possible rotation about the perpendicularaxis by approximately half but would still provide more opportunity formovement than no reduction at all. It is contemplated that the smallerdiameter section could be either before or after the sealing surface, ormay be a larger diameter section in the bores either before or after theseal, or could be both increased bore diameter and decreased plugdiameter. This embodiment will also work with the typical fluid endsealing set up that has the seal in the plug.

The plugs may also be flangeless. The plugs may be inserted until theyare flush with the fluid end body. A separate plate may be used toretain the plugs in position during operation or the plugs may bethreaded on their outside diameter to engage a matching thread on theinside of the bores of the fluid end body. If threaded, the diametralclearances obtained by either increasing the bore dimeters, reducing theplug diameters, or both, may only be of assistance until the threadsengage at which point the possibility of perpendicular axial rotation iseliminated, however, the increased clearance will still reduce thefriction and thus the torque required to assemble and disassemble.

Appendix J: Two-Piece Fluid End

The fluid ends described above may be made in two pieces, as shown anddescribed with reference to FIGS. 153-167. For the purposes of thefollowing description of FIGS. 153-167, reference numerals exclusive tothose FIGS. will be used.

In fluid ends known in the art, such as the fluid end J300 shown inFIGS. 166 and 167, a flange is machined into a fluid end body to providea connection point for a plurality of stay rods. A flange J302 is shownformed in a fluid end body J304 in FIGS. 166 and 167. A plurality ofstay rods J306 interconnect a power end J308 and the flange J302. Theinventors have recognized that current fluid end designs including thosein FIGS. 166-167 are problematic for several reasons.

The machining required to create a flange reduces the strength of thefluid end and produces stress concentrations that reduce the effectivelife of the fluid end. Machining the flange into the fluid end alsoentails wastage of significant amounts of removed raw material, andrequires a significant investment of time and labor. These factorsresult in increased manufacturing costs.

One solution to the issues a machined flange presents is to remove theflange and attach the stay rods directly to the fluid end body. However,this solution requires uniquely designed stay rods that must be replacedwith the fluid end each time the fluid end reaches the end of itslifespan. Such an approach may thus be disadvantageous during actualoperation of the device.

To address these problems, the inventors have designed amulti-body-piece fluid end, embodiments of which are shown in FIGS.153-165. Such designs, particularly those that are flangeless, may leadto less stress being placed on the fluid end during operation, resultingin increased product life. This design also uses fewer raw materials,reducing manufacturing costs. Still further, the construction of thefluid end permits it to be attached to a power end using traditionalstay rods.

In general, fluid ends with multiple body pieces are contemplated by thepresent disclosure. Thus, the fluid end body is not formed from amonolithic piece of material as in certain prior art designs. As will bedescribed below, FIGS. 153-154, for example, illustrate a fluid end withtwo body pieces, J20 and J22; this design achieves savings in rawmaterials (and thus cost), and also leads to less stress on the fluidend during operation, in part because of the flangeless design. That is,neither of body pieces J20 or J22 includes a flange, such as flange J302shown in FIGS. 166-167. As used herein, a “flange” is used according toits ordinary meaning in the art, and includes a piece of a structuralmember that has a wider portion as compared to another portion of thestructural member, such as a rim, rib, collar, plate, ring, etc. InFIGS. 166-167, for example, the flanged member has the shape of a halfI-beam, or alternately a sideways “T”-shape. As used herein, a“flangeless” fluid end body piece is one that does not include a flange.

In embodiments with two body pieces, the second body piece, uponinstallation, is closer to the power end than the first body piece. Insuch an arrangement, a front side of the second body piece may engagewith a back side of the front body piece in various manners. In certainembodiments, the first and second body pieces may be in flushengagement, meaning that the entire surface of the front side of thesecond body piece (excluding bores and through holes since these areashave no surface) is in contact with the back side of the first bodypiece. The concept of flush engagement thus includes embodiments inwhich the front side of the second body piece and the back side of thefirst body piece have the same surface dimensions, as well asembodiments in which the back side of the front body piece has at leastone surface dimension that is larger than a corresponding surfacedimension of the front side of the second body piece. In the formerscenario, the front side of the second body piece may be said to alignwith and abut the back side of the first body piece. In otherembodiments, the front side of the second body piece might have one ormore beveled edges, such that it has slightly smaller dimensions thanthe back side of the first body piece. Flush engagement between thefront side of the second body piece and the back side of the first bodypiece includes embodiments in which the engaging portions of the twosurfaces are planar, as well as embodiments in which the surfaces arenot planar. Alternately, the front side of the second body piece may bepartially engaged with the back side of the second body piece, meaningthat not every portion of the front side of the second body piececontacts a portion of the back side of the first body piece. Note thatpartial engagement between the two body pieces may exist both when thetwo pieces have the same surface dimensions (for example, certainportions of one or both of the pieces may project such that only thoseportions contact the other piece), as well as when the second body piecehas at least one surface dimension that is greater than a correspondingsurface dimension of the first body piece.

The present disclosure also contemplates fluid ends with more than twobody pieces. For instance, the front side of the second body piece mayengage with the back side of the first body piece via one or more spacerelements. For example, washers might be used to separate the first andsecond body pieces at a distance. In other embodiments, the spacerelement may be a thin intervening body piece configured to be situatedbetween the first and second body pieces. The portion of the fluid endnearest the power end upon installation can also be composed of multipleindividual pieces (“a plurality of second fluid end body pieces”), eachof which has a front side that can engage with the back side of thefirst body in one of the various manners described above. Whether theportion of the fluid end nearest the power end is composed of a singlepiece or two or more sub-pieces, this portion being flangeless mayadvantageously reduce internal stress on the fluid end and extend itslife.

Turning now to the figures, FIGS. 153-154 show a fluid end J10 with twobody pieces attached to a power end J12. The power end J12 comprises ahousing J14 having a mounting plate J16 formed on its front end. Aplurality of stay rods J18 attach to the mounting plate J16 and projectfrom its surface. As will be discussed in more detail later herein, thefluid end J10 attaches to the projecting ends of the stay rods J18.

The fluid end J10 comprises a first body J20 releasably attached to aseparate second body J22. The first and second bodies J20 and J22 bothhave a plurality of flat external surfaces J24, J26. Each surface J24,J26 may be rectangular in shape. The exterior surfaces J24 and J26 ofeach body J20 and J22 may be joined in the shape of a rectangular prism.However, the corner edges of such prism may be beveled. As will bediscussed in more detail later herein, a back side J28 of the first bodyJ20 is attached to a front side J30 of the second body J22. The bodiesJ20 and J22 are attached such that a portion of the external surface J24of the first body J20 is in flush engagement with a portion of theexternal surface J26 of the second body J22.

With reference to FIG. 156, a plurality of rectilinear first bores J32are formed in the first body J20. The plural first bores J32 arearranged in side-by-side relationship. Each of the first bores J32extends through the entirety of the first body J20, interconnecting thetop and bottom ends J34 and J36. At each of its opposed ends J34 andJ36, the first bore J32 opens at the external surface J24. The diameterof each first bore J32 may vary throughout its length. Adjacent the topend J34 of the first body J20, each first bore J32 is closed by aninstalled component J38, as shown in FIG. 155. Each component J38 isreleasably held within its first bore J32 by a retainer element J40 andfastening system J42, as shown in FIGS. 153-155, 157 and 158.

The components J38, retainer elements J40, and fastening system J42shown in FIG. 155 comprise those described in U.S. patent applicationSer. No. 16/035,126, authored by Foster, et al. (the '126 application).Likewise, the inner components of the fluid end J10, shown in FIG. 155,may comprise those inner components described in the '126 application.

At the bottom end J36 of the first body J20, each of the first bores J32is joined by a conduit J44 to an inlet manifold J46, as shown in FIGS.153-154. Fluid enters the fluid end J10 through the conduits J44 of theinlet manifold J46.

Continuing with FIG. 156, a plurality of rectilinear second bores J48are formed in the first body J20. The plural second bores J48 arearranged in side-by-side relationship. Each of the second bores J48extends through the entirety of the first body J20, interconnecting thefront and back sides J50 and J28. At each of its opposed sides J50 andJ28, each second bore J48 opens at the external surface J24. Each of thesecond bores J48 intersects a corresponding one of the first bores J32.Each second bore J48 may be disposed in orthogonal relationship to itsintersecting first bore J32.

Adjacent the front side J50 of the first body J20, each second bore J48is closed by an installed component J52, as shown in FIG. 155, which maybe identical to the component J38. Each component J52 is releasably heldwithin its second bore J48 by a retainer element J54 and fasteningsystem J56, as shown in FIGS. 153-155 and 157. The retainer element J54may be identical to the retainer element J40, and the fastening systemJ56 may be identical to the fastening system J42.

With reference to FIGS. 156, 158 and 159, a plurality of rectilinearbores J58, one of which is shown in FIG. 156, are formed in the secondbody J22. The bores J58 are arranged in side-by-side relationship. Eachof the bores J58 extends through the entirety of the second body J22,interconnecting the front and back sides J30 and J60. At each of itsopposed sides J30 and J60, each bore J58 opens at the external surfaceJ26. Each bore J58 includes a counterbore J59 formed adjacent the backside J60 of the second body J22, as shown in FIGS. 156 and 158. Eachbore J58 formed in the second body J22 registers with a correspondingone of the second bores J48 formed in the first body J20. When thebodies J20 and J22 are joined and aligned, each bore J58 becomes anextension of its associated second bore J48, as shown in FIG. 156.

With reference to FIG. 155, a plunger J62 is installed within each pairof aligned bores J48 and J58. A sealing arrangement J64 is installedwithin each pair of aligned bores J48 and J58, and surrounds the plungerJ62 within those bores. Each sealing arrangement J64 comprises astuffing box sleeve J66 that houses a series of annular packing sealsJ71. The stuffing box sleeves J66 and packing seals J71 may be selectedfrom those described in the '126 application.

A retainer element J68 is installed within each bore J58, and holds thestuffing box sleeve J66 within such bore. Each retainer element J68 issecured to a flat bottom J69 of the counterbore J59 of its associatedbore J58. A fastening system J70 holds the retainer element J68 inplace. The seals J71 are compressed by a packing nut J72 threaded intoan associated retainer element J68. The retainer elements J68, fasteningsystem J70, plungers J62, and packing nuts J72 may be selected fromthose described in the '126 application.

Turning back to FIGS. 153-154, the power end J12 comprises a pluralityof pony rods J74. Pony rods are known in the art as elongate rods thatinterconnect the crankshaft of a power end to each of the plungerspositioned within a fluid end. Each pony rod J74 extends through acorresponding opening formed in the mounting plate J16. Each pony rodJ74 is attached to a corresponding one of the plungers J62 by means of aclamp J76. An engine attached to the power end J12 drives reciprocatingmovement of the pony rods J74. Such movement of the pony rods J74 causeseach plunger J62 to reciprocate within its associated pair of alignedbores J48 and J58. High pressure fluid pumped through the fluid end J10by the plungers J62 exits the fluid end J10 through one or more outletconduits J78.

With reference to FIGS. 158 and 159, each stay rod J18 comprises acylindrical body J84 having opposed first and second ends J80 and J82.External threads are formed in the body J84 adjacent each of its endsJ80 and J82. These threaded portions of the body J84 are of lesserdiameter than the rest of the body J84. A step separates each threadedportion of the body from its unthreaded portion. Step J85 is situatedadjacent the first end J80, and step J86 is situated adjacent the secondend J82.

Continuing with FIG. 159, a plurality of internally threaded connectorsJ88 are supported on the front surface of the mounting plate J16. Eachconnector J88 mates with the threaded first end J80 of a correspondingstay rod J18. An integral nut J90 is formed on each stay rod J18adjacent its first end J80. The nut J90 provides a gripping surfacewhere torque may be applied to the stay rod J18 during installation.Once a stay rod J18 has been installed in a connector J88, its secondend J82 projects from the front surface of the mounting plate J16. Inalternative embodiments, the stay rods J18 may thread directly intoholes formed in the mounting plate.

With reference to FIGS. 160-162, the second body J22 is secured to thestay rods J18 using a fastening system J92. The fastening system J92includes a plurality of washers J94 and a plurality of internallythreaded nuts J96. A plurality of bores J98 are formed about theperiphery of the second body J22. The number of bores J98 may equal thenumber of stay rods J18. A single stay rod J18 is installed within eachof the bores J98, at its second end J82, as shown in FIG. 162. Each boreJ98 includes a counterbore J100 formed adjacent the front side J30 ofthe second body J22, as shown in FIGS. 160 and 162. Adjacentcounterbores J100 may overlap each other, as shown in FIGS. 160 and 161.In alternative embodiments, each bore may be spaced from each adjacentbore such that their respective counterbores do not overlap.

A stay rod J18 is installed by inserting its second end J82 into theopening of the bore J98 formed in the back side J60 of the second bodyJ22. The stay rod J82 is extended into the bore J98 until the step J86abuts the back side J60, as shown in FIG. 162.

When a stay rod J18 is installed, its second end J82 projects within thecounterbore J100 of its associated bore J98. To secure each stay rod J18to the second body J22, a washer J94 and nut J96 are installed on thesecond end J82 of the stay rod J18, as shown in FIGS. 161 and 162. Eachnut J96 and its underlying washer J94 press against a flat bottom J102of the counterbore J100 within which they are installed. Each nut J96 isfully submerged within its recessed counterbore J100.

With reference to FIGS. 155-158, the first body J20 is secured to thesecond body J22 using a fastening system J104. The fastening system J104comprises a plurality of studs J106, a plurality of washers J108, andplurality of internally threaded nuts J110. Each stud J106 comprises acylindrical body J116 having a pair of opposed ends J112 and J114, asshown in FIGS. 155-157. Each of the ends J112 and J114 is externallythreaded.

A plurality of internally threaded openings J118 are formed about theperiphery of the first body J20, as shown in FIGS. 155-157. The firstend J112 of each stud J106 mates with a corresponding one of theopenings J118. Once a stud J106 has been installed in the first bodyJ20, its second end J114 projects from the body's external surface J24,as shown in FIG. 158.

A plurality of through-bores J120 are formed about the periphery of thesecond body J22, as shown in FIGS. 155-157. The through-bores J120 arealignable with the plural studs J106 projecting from the first body J20.

To assemble the first and second bodies J20 and J22, the plural studsJ106 are installed in the plural openings J118 of the first body J20.The first body J20 and installed studs J106 are positioned such thateach through-bore J120 formed in the second body J22 is aligned with acorresponding stud J106. The first and second bodies J20 and J22 arethen brought together such that each stud J106 is received within acorresponding through-bore J120. When the bodies J20 and J22 are thusjoined, the second end J114 of each stud J106 projects from the backside J60 of the second body J22. Finally, a washer J108 and nut J110 areinstalled on the second end J114 of each stud J106, as shown in FIGS.154-157, thereby securing the bodies together.

Continuing with FIG. 157, one or more pin bores J122 may be formed inthe first body J20 adjacent its outer edges. Each pin bore J122 mayreceive a pin J124 that projects from the external surface J24 of thefirst body J20, as shown in FIGS. 157 and 158. These pins J124 may beinstalled within a corresponding bore J126 formed in the second bodyJ22, as shown in FIGS. 157 and 158. The pins J124 help align the firstand second bodies J20 and J22 during assembly of the fluid end J10.

The concept of a “kit” is described herein due to the fact that fluidends are often shipped or provided unassembled by a manufacturer, withthe expectation that an end customer will use components of the kit toassemble a functional fluid end. Accordingly, certain embodiments withinthe present disclosure are described as “kits,” which are unassembledcollections of components. The present disclosure also describes andclaims assembled apparatuses and systems by way of reference tospecified kits, along with a description of how the various kitcomponents are actually coupled to one another to form the apparatus orsystem.

Several kits are useful for assembling the fluid end J10. A first kitcomprises the first body J20 and the second body J22. The first kit mayalso comprise the fastening system J92 and/or the fastening system J104.The first kit may further comprise the components J38 or J52, sealingarrangements J64, retainer elements J40, J54 or J68, fastening systemsJ42, J56 or J70, packing nuts J72, plungers J62, and/or clamps J72,described herein.

With reference to FIGS. 158-160, the positioning of the bores J98 aroundthe periphery of the second body J22 corresponds with the positioning ofthe stay rods J18 on the mounting plate J16. Thus, each second body J22is constructed specifically to match different stay rod J18 spacingconfigurations known in the art.

As shown in FIGS. 154-158, the second body J22 has a lesser thicknessthan the first body J20 (thickness being measured in FIG. 154 along theline A-A, for example). However, the bodies J20 and J22 have the samedepth and height, so that they form a rectangular prism when assembled.Thus, the front side of the second fluid end body and the back side ofthe first fluid body may have the same dimensions in some embodiments.In other embodiments, the dimensions of these opposing sides may bedifferent. Also, it is noted that the corner edges of such prism may bebeveled.

The first and second bodies J20, J22 may be formed from a strong durablematerial, such as steel. Because the first body J20 must receive fluidsunder conditions of high pressure, it may be formed from stainless steelor cast iron. In contrast, the second body J22 does not receive highpressure fluids: it serves only as a connection between the power endJ12 and the first body J20. The second body J2 can thus be formed from adifferent, lower strength, and less costly material than the first bodyJ20. For example, when the first body J20 is formed from stainlesssteel, the second body can be formed from a less costly alloy steel.Alternatively, the first and second bodies may be formed from the samematerial, such as stainless steel.

In order to manufacture the fluid end J10, the first and second bodiesJ20 and J22 are each cut to size from blocks of steel. Multiple first orsecond bodies J20 or J22 may be forged from the same block. In suchcase, the bodies J20 and J22 may be forged by dividing the blockparallel to its length into multiple rectangular pieces. Because aflange is not forged from the block, material that is typicallydiscarded may instead be used to form one of the first or second bodiesJ20 or J22. If the bodies J20 and J22 are formed from the same material,the first and second body J20 and J22 may be forged from the same block.

After the bodies J20 and J22 are formed, the bores and openingsdescribed herein are machined into each body J20 and J22. The studsJ106, as well as the internal components shown in FIG. 155, includingthe components J38, retainer elements J40 and fastening system J42, arenext installed in the first body J20. After the necessary bores havebeen formed in the second body J22, the sealing arrangements J64,retainer elements J68, fastening system J70, plungers J62 and packingnuts J72 described herein are installed. Prior to operation, the secondbody J22 is attached to the power end J12, and the first body J20 isattached to the second body J22.

During operation, the pumping of high-pressure fluid through the fluidend J10 causes it to pulsate or flex. Such motion applies torque to thefluid end J10. The amount of torque applied to the fluid end J10corresponds to the distance between the power end J12 and the front sideJ50 of the fluid end: the moment arm.

In flanged fluid ends, such as the fluid end J300 shown in FIGS. 166 and167, the applied torque is known to cause fatigue failures at theflanged connection point. A flanged connection point J310 is shown inFIGS. 166 and 167. Flanged fluid ends require space between the flangeand the fluid end body to operate a wrench, as shown by a space J312.Such space is not needed with the fluid end J10. Thus, the moment armassociated with the fluid end J10 is decreased from that associated withflanged fluid ends. Therefore, less torque is applied to the fluid endJ10 during operation than flanged fluid ends, which makes the fluid endJ10 less susceptible to fatigue failures.

Turning to FIGS. 163-165, an alternative embodiment of a fluid end J200is shown. The fluid end J200 comprises a first body J202 attached toseparate second body J204. The second body J204 is machined to have alesser thickness than that of the second body J22, shown in FIGS.153-154. As described later herein, providing the second body J204 witha lesser thickness allows the first and second bodies J202 and J204 tobe attached together using a single fastening system.

Continuing with FIGS. 163-165, the first and second bodies J202 and J204each have a plurality of flat external surfaces J206 and J208. Thesurfaces J206 and J208 may be rectangular in shape. The exteriorsurfaces J206 and J208 of each body J202 and J204 may be joined in theshape of a rectangular prism. However, the corner edges of such prismmay be beveled.

With reference to FIG. 165, a plurality of rectilinear first bores J210,one of which is shown in FIG. 165, are formed in the first body J202.The plural bores J210 are arranged in side-by-side relationship. Eachfirst bore J210 extends through the entirety of the first body J202,interconnecting its top and bottom ends J212 and J214. At each of itsopposed ends J212 and J214, the first bore J210 opens at the externalsurface J206.

Adjacent the top end J212 of the first body J202, each first bore J210is closed by an installed component J213. Each component J213 isreleasably held within its first bore J210 by a retainer element J215and fastening system J217, as shown in FIGS. 163-165. The componentsJ213, retainer elements J215, and fastening system J217 may be selectedfrom those described in the '126 application.

Continuing with FIG. 165, a plurality of rectilinear second bores J216are formed in the first body J202. The plural second bores J216 arearranged in side-by-side relationship. Each second bore J216 extendsthrough the entirety of the first body J202, interconnecting its frontand back sides J218 and J220. At each of its opposed sides J218 andJ220, each second bore J216 opens at the external surface J206. Thesecond bores J216 each intersect a corresponding one of the first boresJ210. Each second bore J216 may be disposed in orthogonal relationshipto its intersecting first bore J210.

Adjacent the front side J218, each second bore J216 is closed by aninstalled component J221, which may be identical to the component J213.Each component J221 is releasably held within its second bore J216 by aretainer element J223 and fastening system J225, as shown in FIGS. 164and 165. The retainer element J223 may be identical to the retainerelement J215, and the fastening system J225 may be identical to thefastening system J217.

Continuing with FIG. 165, a plurality of bores J222, one of which isshown in FIG. 165, are formed in the second body J204. The bores J222are arranged in side-by-side relationship. Each bore J222 extendsthrough the entirety of the second body J204, interconnecting its frontand back sides J224 and J226. At each of its opposed sides J224 andJ226, each bore J222 opens at the external surface J208. Each bore J222formed in the second body J204 registers with a corresponding one of thesecond bores J216 formed in the first body J202. When the bodies J202and J204 are joined and aligned, each bore J222 becomes an extension ofits associated second bore J216.

With reference to FIG. 164, a plurality of bores J228 are formed in theouter periphery of the first body J202. Each bore J228 includes acounterbore J230 positioned immediately adjacent the front side J218 ofthe first body J202. The bores J228 are each alignable with a pluralityof corresponding through-bores J232 formed about the periphery of thesecond body J204, as shown in FIGS. 163-164.

A fastening system is used to secure the first body J202 to the secondbody J204. The fastening system comprises a plurality of stay rods,similar to stay rods J18, and a plurality of nuts and washers. The stayrods are installed within each aligned bore J228 and J232. A nut andwasher is torqued on the end of each stay rod within each correspondingcounterbore J230. The bodies J202 and J204 are attached such that theback side J220 of the first body J202 is in flush engagement with thefront side J224 of the second body J204.

Continuing with FIG. 164, in order for a stay rod to extend the lengthbetween the first and second bodies J202 and J204, the second body J204is machined to have a lesser thickness than the second body J22, shownin FIGS. 153-158. Such decrease in size is possible because a pluralityof sealing arrangements J234 used with the second body J204 areprimarily positioned outside of the second body J204, as shown in FIG.165. Each sealing arrangement J234 comprises a stuffing box sleeve J236that houses a series of packing seals J238. The stuffing box sleevesJ236 and packing seals J238 may be selected from those described in the'126 application.

As shown in FIG. 165, each bore J222 formed in the second body J204includes a counterbore J242 that opens on the back side J226 of thesecond body J204. A removable box gland J240 is closely received withineach counterbore J242. The removable box glands J240 are each tubularsleeves having open first and second ends J241 and J244. Each second endJ244 has a flanged outer edge J245 that is sized to be closely receivedwithin each counterbore J242. Each sealing arrangement J234 is housed atleast partially within a corresponding removable box gland J240.

A plurality of openings J246 are formed in the flanged outer edge J245of each box gland J240. The openings J246 correspond with a plurality ofopenings (not shown) formed in a flat bottom J250 of each counterboreJ242. A plurality of fasteners may be installed within the opening J246and the opening formed in the bottom J250. When installed, the fastenersreleasably secure each box gland J240 to the second body J204.

Continuing with FIG. 163-165, a retainer element J252 and fasteningsystem hold the sleeve J236 within the box gland J240 and aligned withbores J222 and J242, as shown in FIG. 165. The retainer element J252 andfastening system may be the same as the retainer element J68 andfastening system J70, as shown in FIG. 155. The seals J238 arecompressed by a packing nut J254 threaded into an associated retainerelement J252, as shown in FIG. 165. A plunger J258 is installed withineach pair of aligned bores J216 and J222.

Several kits are useful for assembling the fluid end J200. A first kitcomprises the first body J202 and the second body J204. The first kitmay also comprise the fastening system described with reference to FIG.165 to attach the bodies J202 and J204. The first kit may furthercomprise the components J213 or J221, removable box glands J240, sealingarrangements J234, retainer elements J215, J223 or J252, fasteningsystem J217, J225 or the fastening system used with the box gland J240,packing nuts J254, and/or plungers J258, described herein.

The bodies J202 and J204 may be formed of the same material as thebodies J20 and J22. Likewise, the bodies J202 and J204 may bemanufactured in the same manner as the bodies J20 and J22.

The plurality of washers used with each fastening system J92 and J104,shown in FIGS. 155-158, 161 and 162, may be configured to allow a largeamount of torque to be applied to the nuts without using a reaction arm.Instead, the washer itself may serve as the counterforce needed totorque a nut onto a stud. Not having to use a reaction arm increases thesafety of the assembly process. The same is true for the washers thatmay be used with the fastening system described with reference to FIG.164.

The nuts used with the fastening systems J92 and J104 may also comprisea hardened inner layer to help reduce galling between the threads of thenuts and studs during the assembly process. The same is true for thenuts that may be used with the fastening system described with referenceto FIG. 164. An example of the above described washers, nuts, andmethods are described in Patent Cooperation Treaty Application SerialNo. PCT/US2017/020548, authored by Junkers, et al.

Changes may be made in the construction, operation and arrangement ofthe various parts, elements, steps and procedures described herein. Forexample, certain embodiments of the second fluid end body piece (orpieces) are described above as “flangeless.” In other embodiments, aminimally flanged fluid end body piece may also be utilized. Considerthe surface dimension of the wider portion of the flanged piece to thenarrower portion of the piece—for example, the height of the portion offlange J302 in FIG. 166 to the height of the narrower portion thatengages with the first body piece. In one set of embodiments, the ratior of the height (or other corresponding surface dimension) of thenarrower portion to the height (or other corresponding surfacedimension) of the wider portion may be 0.90<r<1.0; in other embodimentsthe ratio r may be 0.95<r<1.0.

The various features and alternative details of construction of theapparatuses described herein for the practice of the present technologywill readily occur to the skilled artisan in view of the foregoingdiscussion, and it is to be understood that even though numerouscharacteristics and advantages of various embodiments of the presenttechnology have been set forth in the foregoing description, togetherwith details of the structure and function of various embodiments of thetechnology, this detailed description is illustrative only, and changesmay be made in detail, especially in matters of structure andarrangements of parts within the principles of the present technology tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

The invention claimed is:
 1. A fluid end, comprising: a fluid end bodyincluding a plurality of bore pairs, wherein a given bore pair of theplurality of bore pairs comprises intersecting horizontal and verticalbores; and a connect plate mounted such that at least a portion of theconnect plate is in flush engagement with the fluid end body, whereinthe connect plate is configured to interface between the fluid end bodyand a power source external to the fluid end using a plurality of stayrods that extend between the connect plate and the power source, inwhich the fluid end does not include a flange configured for connectionto the power source.
 2. The fluid end of claim 1 in which the fluid endbody is made of a first material and the connect plate is made of asecond material.
 3. The fluid end body of claim 2 in which the firstmaterial comprises stainless steel.
 4. The fluid end body of claim 2 inwhich the first material is harder than the second material.
 5. Thefluid end body of claim 2 in which the second material is carbon steel.6. The fluid end of claim 1, wherein the connect plate comprises aplurality of horizontal bores configured to align respectively with thehorizontal bores of the fluid end body, wherein the fluid end furthercomprises a plurality of removable stuffing box sleeves positionedwithin respective horizontal bores of the connect plate, wherein a givenremovable stuffing box sleeve is configured to receive a correspondingplunger configured to be driven by the power source.
 7. The fluid end ofclaim 6, wherein the fluid end body includes a recess configured toreceive a replaceable seal, wherein the replaceable seal is configuredto interface between the fluid end body and the given removable stuffingbox sleeve.
 8. The fluid end of claim 1, further comprising: a pluralityof removable plugs inserted within individual bores of the plurality ofbore pairs.
 9. The fluid end of claim 8, further comprising a pluralityof retainers configured to retain the plugs within the fluid end body.10. The fluid end of claim 9, wherein each of the plurality of retainershas no externally-disposed threaded surface.
 11. The fluid end of claim9, wherein each of the plurality of retainers is secured to the fluidend body using a fastening system.
 12. The fluid end of claim 11,wherein the fastening system comprises a plurality of studs, a pluralityof nuts, and a plurality of washers.
 13. The fluid end of claim 9,wherein the plurality of retainers each include respective centralretainer nuts, wherein for a given one of the retainers, a correspondingcentral retainer nut is removable to access a given individual borewithout requiring removal of the given retainer.
 14. The fluid end ofclaim 8, wherein for a given one of the plurality of removable plugsinserted within a given individual bore, the walls surrounding the givenindividual bore of the fluid end body include a recess configured toreceive a replaceable seal, wherein the replaceable seal is configuredto interface between the fluid end body and the given removable plug.15. The fluid end of claim 8, wherein the plurality of removable plugsincludes suction plugs and discharge plugs.
 16. The fluid end of claim1, further comprising: a plurality of removable valves installed withinindividual bores of the plurality of bore pairs.
 17. The fluid end ofclaim 16, wherein each of the plurality of valves comprises a valve seatand a valve body, wherein each valve seat is configured to engage with acorresponding valve body.
 18. The fluid end of claim 17, wherein thevalve seat comprises a hardened insert configured to engage with thevalve body.
 19. The fluid end of claim 18, wherein the hardened insertis made of tungsten carbide.
 20. The fluid end of claim 19 in which anouter surface of the valve seat includes a tapered section.
 21. Thefluid end of claim 1, further comprising: a safety system attached tothe fluid end body, the safety system comprising a plurality of eyebolts and one or more cables.
 22. The fluid end of claim 1, in which theconnect plate is attached to the fluid end body using a plurality ofstuds and nuts.
 23. The fluid end of claim 1, in which an end of each ofthe plurality of stay rods is attached to the connect plate.
 24. Amethod of manufacturing a fluid end, the method comprising: forming afluid end body so that the fluid end body includes a plurality of borepairs, wherein a given bore pair of the plurality of bore pairscomprises intersecting horizontal and vertical bores; and forming aconnect plate so that the connect plate is configured to be mounted suchthat at least a portion of the connect plate is in flush engagement withthe fluid end body and is configured to interface between the fluid endbody and a power source external to the fluid end body using a pluralityof stay rods that extend between the connect plate and the power source,in which the fluid end does not include a flange configured forconnection to the power source.
 25. The method of claim 24, wherein thefluid end body is formed from a first material and the connect plate isformed from a second material.
 26. The method of claim 25, wherein thefirst material is stainless steel and the second material is carbonsteel.
 27. The method of claim 25, wherein the first material is harderthan the second material.
 28. The method of claim 24, furthercomprising: removably attaching the connect plate to the fluid end body.29. The method of claim 25, further comprising: dividing a single blockof the first material parallel to its length into multiple blocks; andforming multiple fluid end bodies from respective ones of the multipleblocks.